C Basic: Exercises, Practice, Solution

C Basic Declarations and Expressions [150 exercises with solution]

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1. Print name, DOB, and mobile number

Write a C program to print your name, date of birth, and mobile number.
Expected Output:

Name   : Alexandra Abramov  
DOB    : July 14, 1975  
Mobile : 99-9999999999

Click me to see the solution

2. Get the C version in use

Write a C program to get the C version you are using.
Expected Output:

We are using C18!

Click me to see the solution

3. Print block 'F' and a large 'C'

Write a C program to print a block F using the hash (#), where the F has a height of six characters and width of five and four characters. And also print a very large 'C'.
Expected Output:

######
#
#
#####
#
#
#

    ######
  ##      ##
 #
 #
 #
 #
 #
  ##      ##
    ######

Click me to see the solution

4. Reverse characters ('X', 'M', 'L')

Write a C program to print the following characters in reverse.
Test Characters: 'X', 'M', 'L'
Expected Output:
The reverse of XML is LMX
Click me to see the solution

5. Compute rectangle perimeter and area

Write a C program to compute the perimeter and area of a rectangle with a height of 7 inches and width of 5 inches.
Expected Output:
Perimeter of the rectangle = 24 inches
Area of the rectangle = 35 square inches
Click me to see the solution

6. Compute circle perimeter and area

Write a C program to compute the perimeter and area of a circle with a given radius.
Expected Output:
Perimeter of the Circle = 37.680000 inches
Area of the Circle = 113.040001 square inches
Click me to see the solution

7. Display multiple variables of various types

Write a C program to display multiple variables.
Sample Variables :
a+ c, x + c,dx + x, ((int) dx) + ax, a + x, s + b, ax + b, s + c, ax + c, ax + ux
Declaration :
int a = 125, b = 12345;
long ax = 1234567890;
short s = 4043;
float x = 2.13459;
double dx = 1.1415927;
char c = 'W';
unsigned long ux = 2541567890;
Click me to see the solution

8. Convert days to years, weeks, and days

Write a C program to convert specified days into years, weeks and days.
Note: Ignore leap year.

Test Data :
Number of days : 1329
Expected Output :
Years: 3
Weeks: 33
Days: 3
Click me to see the solution

9. Calculate sum of two integers

Write a C program that accepts two integers from the user and calculates the sum of the two integers.
Test Data :
Input the first integer: 25
Input the second integer: 38
Expected Output:
Sum of the above two integers = 63
Click me to see the solution

10. Calculate product of two integers

Write a C program that accepts two integers from the user and calculates the product of the two integers.
Test Data :
Input the first integer: 25
Input the second integer: 15
Expected Output:
Product of the above two integers = 375
Click me to see the solution

11. Calculate average weight for purchases

Write a C program that accepts two item's weight and number of purchases (floating point values) and calculates their average value.
Test Data :
Weight - Item1: 15
No. of item1: 5
Weight - Item2: 25
No. of item2: 4
Expected Output:
Average Value = 19.444444
Click me to see the solution

12. Print employee ID and monthly salary

Write a C program that accepts an employee's ID, total worked hours in a month and the amount he received per hour. Print the ID and salary (with two decimal places) of the employee for a particular month.
Test Data :
Input the Employees ID(Max. 10 chars): 0342
Input the working hrs: 8
Salary amount/hr: 15000
Expected Output:
Employees ID = 0342
Salary = U$ 120000.00
Click me to see the solution

13. Find the maximum of three integers

Write a C program that accepts three integers and finds the maximum of three.
Test Data :
Input the first integer: 25
Input the second integer: 35
Input the third integer: 15
Expected Output:
Maximum value of three integers: 35
Click me to see the solution

14. Calculate bike’s average consumption

Write a C program to calculate a bike’s average consumption from the given total distance (integer value) travelled (in km) and spent fuel (in litters, float number – 2 decimal points).
Test Data :
Input total distance in km: 350
Input total fuel spent in liters: 5
Expected Output:
Average consumption (km/lt) 70.000
Click me to see the solution

15. Calculate distance between two points

Write a C program to calculate the distance between two points.
Test Data :
Input x1: 25
Input y1: 15
Input x2: 35
Input y2: 10
Expected Output:
Distance between the said points: 11.1803
Click me to see the solution

16. Break amount into smallest banknotes

Write a C program to read an amount (integer value) and break the amount into the smallest possible number of bank notes.
Test Data :
Input the amount: 375
Expected Output:
There are:
3 Note(s) of 100.00
1 Note(s) of 50.00
1 Note(s) of 20.00
0 Note(s) of 10.00
1 Note(s) of 5.00
0 Note(s) of 2.00
0 Note(s) of 1.00
Click me to see the solution

17. Convert seconds into hours, minutes, seconds

Write a C program to convert a given integer (in seconds) to hours, minutes and seconds.
Test Data :
Input seconds: 25300
Expected Output:
There are:
H:M:S - 7:1:40
Click me to see the solution

18. Convert days to years, months, days

Write a C program to convert a given integer (in days) to years, months and days, assuming that all months have 30 days and all years have 365 days.
Test Data :
Input no. of days: 2535
Expected Output:
6 Year(s)
11 Month(s)
15 Day(s)
Click me to see the solution

19. Validate four integers based on conditions

Write a C program that accepts 4 integers p, q, r, s from the user where q, r and s are positive and p is even. If q is greater than r and s is greater than p and if the sum of r and s is greater than the sum of p and q print "Correct values", otherwise print "Wrong values".
Test Data :
Input the second integer: 35
Input the third integer: 15
Input the fourth integer: 46
Expected Output:
Wrong values
Click me to see the solution

20. Solve quadratic equation using Bhaskara's formula

Write a C program to print the roots of Bhaskara’s formula from the given three floating numbers. Display a message if it is not possible to find the roots.
Test Data :
Input the first number(a): 25
Input the second number(b): 35
Input the third number(c): 12
Expected Output:
Root1 = -0.60000
Root2 = -0.80000
Click me to see the solution

21. Check integer range or error for negative > 80

Write a C program that reads an integer and checks the specified range to which it belongs. Print an error message if the number is negative and greater than 80.
Test Data :
Input an integer: 15
Expected Output:
Range [0, 20]
Click me to see the solution

22. Sum all odd numbers among five inputs

Write a C program that reads 5 numbers and sums all odd values between them.
Test Data :
Input the first number: 11
Input the second number: 17
Input the third number: 13
Input the fourth number: 12
Input the fifth number: 5
Expected Output:
Sum of all odd values: 46
Click me to see the solution

23. Check for valid triangle and calculate perimeter

Write a C program that reads three floating-point values and checks if it is possible to make a triangle with them. Determine the perimeter of the triangle if the given values are valid.
Test Data :
Input the first number: 25
Input the second number: 15
Input the third number: 35
Expected Output:
Perimeter = 75.0
Click me to see the solution

24. Check if two integers are multiples

Write a C program that reads two integers and checks whether they are multiplied or not.
Test Data :
Input the first number: 5
Input the second number: 15
Expected Output:
Multiplied!
Click me to see the solution

25. Get month name from number (1–12)

Write a C program that reads an integer between 1 and 12 and prints the month of the year in English.
Test Data :
Input a number between 1 to 12 to get the month name: 8
Expected Output:
August
Click me to see the solution

26. Print all even numbers between 1 and 50

Write a C program that prints all even numbers between 1 and 50 (inclusive).
Test Data :
Even numbers between 1 to 50 (inclusive):
Expected Output:
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50
Click me to see the solution

27. Count positive and negative numbers in 5 inputs

Write a C program that reads 5 numbers and counts the number of positive numbers and negative numbers.
Test Data :
Input the first number: 5
Input the second number: -4
Input the third number: 10
Input the fourth number: 15
Input the fifth number: -1
Expected Output:
Number of positive numbers: 3
Number of negative numbers: 2
Click me to see the solution

28. Count positives and calculate their average from 5 inputs

Write a C program that reads 5 numbers, counts the number of positive numbers, and prints out the average of all positive values.
Test Data :
Input the first number: 5
Input the second number: 8
Input the third number: 10
Input the fourth number: -5
Input the fifth number: 25
Expected Output:
Number of positive numbers: 4
Average value of the said positive numbers: 12.00
Click me to see the solution

29. Sum all odd values among 5 inputs

Write a C program that read 5 numbers and sum of all odd values between them.
Test Data :
Input the first number: 5
Input the second number: 7
Input the third number: 9
Input the fourth number: 10
Input the fifth number: 13
Expected Output:
Sum of all odd values: 34
Click me to see the solution

30. Print squares of all even numbers up to a given value

Write a C program to find and print the square of all the even values from 1 to a specified value.
Test Data :
List of square of each one of the even values from 1 to a 4 :
Expected Output:
2^2 = 4
4^2 = 16
Click me to see the solution

31. Check if an integer is positive/negative and even/odd

Write a C program to check whether a given integer is positive even, negative even, positive odd or negative odd. Print even if the number is 0.
Test Data :
Input an integer: 13
Expected Output:
Positive Odd
Click me to see the solution

32. Print numbers between 1 and 100 with a specific remainder

Write a C program to print all numbers between 1 and 100 which are divided by a specified number and the remainder will be 3.
Test Data :
Input an integer: 25
Expected Output:
3
28
53
78
Click me to see the solution

33. Find the highest value and its position from inputs

Write a C program that accepts some integers from the user and finds the highest value and the input position.
Test Data :
Input 5 integers:
5
7
15
23
45
Expected Output:
Highest value: 45
Position: 5
Click me to see the solution

34. Sum odd numbers between two given integers

Write a C program to compute the sum of consecutive odd numbers from a given pair of integers.
Test Data :
Input a pair of numbers (for example 10,2):
Input first number of the pair: 10
Input second number of the pair: 2
Expected Output:
List of odd numbers: 3
5
7
9
Sum=24
Click me to see the solution

35. Check if a pair of numbers is in ascending/descending order

Write a C program to check if two numbers in a pair are in ascending order or descending order.
Test Data :
Input a pair of numbers (for example 10,2 : 2,10):
Input first number of the pair: 10
Expected Output:
Input second number of the pair: 2
The pair is in descending order!
Click me to see the solution

36. Validate a password (1234 as correct)

Write a C program to read a password until it is valid. For wrong password print "Incorrect password" and for correct password print, "Correct password" and quit the program. The correct password is 1234.
Test Data :
Input the password: 1234
Expected Output:
Correct password
Click me to see the solution

37. Determine quadrant of Cartesian coordinates (x, y)

Write a C program to read the coordinates (x, y) (in the Cartesian system) and find the quadrant to which it belongs (Quadrant -I, Quadrant -II, Quadrant -III, Quadrant -IV).
Note: A Cartesian coordinate system is a coordinate system that specifies each point uniquely in a plane by a pair of numerical coordinates.
These are often numbered from 1st to 4th and denoted by Roman numerals: I (where the signs of the (x,y) coordinates are I(+,+), II (−,+), III (−,−), and IV (+,−).
Test Data :
Input the Coordinate(x,y):
x: 25
y: 15
Expected Output:
Quadrant-I(+,+)
Click me to see the solution

38. Divide two numbers or print if division isn't possible

Write a program that reads two numbers and divides the first number by the second number. If division is not possible print "Division is not possible".
Test Data :
Input two numbers:
x: 25
y: 5
Expected Output: 5.0
Click me to see the solution

39. Sum all numbers between two integers, excluding multiples of 17

Write a C program to calculate the sum of all numbers not divisible by 17 between two given integer numbers.
Test Data :
Input the first integer: 50 Input the second integer: 99
Expected Output:
Sum: 3521
Click me to see the solution

40. Find integers divisible by 7 with a remainder of 2 or 3

Write a C program that finds all integer numbers that divide by 7 and have a remainder of 2 or 3 between two given integers.
Test Data :
Input the first integer: 25
Input the second integer: 45
Expected Output:
30
31
37
38
44
Click me to see the solution

41. Print n lines of 3 consecutive numbers starting from 1

Write a C program to print 3 numbers on a line, starting with 1 and printing n lines. Accept the number of lines (n, integer) from the user.
Test Data :
Input number of lines: 5
Expected Output:
1 2 3
4 5 6
7 8 9
10 11 12
13 14 15
Click me to see the solution

42. Print numbers with their squares and cubes for n lines

Write a C program to print a number, its square and cube, starting with 1 and printing n lines. Accept the number of lines (n, integer) from the user.
Test Data :
Input number of lines: 5
Expected Output:
1 1 1
2 4 8
3 9 27
4 16 64
5 25 125
Click me to see the solution

43. Print p lines of q numbers in sequence starting from 1

Write a C program that reads two integers p and q, prints p number of lines in a sequence of 1 to b in a line.
Test Data :
Input number of lines: 5
Number of characters in a line: 6
Expected Output:
1 2 3 4 5 6
7 8 9 10 11 12
13 14 15 16 17 18
19 20 21 22 23 24
25 26 27 28 29 30
Click me to see the solution

44. Calculate the average of student math marks until termination

Write a C program to calculate the average mathematics marks of some students. Input 0 (excluding to calculate the average) or a negative value to terminate the input process.
Test Data :
Input Mathematics marks (0 to terminate): 10
15
20
25
0
Expected Output:
Average marks in Mathematics: 17.50
Click me to see the solution

45. Compute series sum S=1+1/2+1/3+...+1/50

Write a C program to calculate the value of S where S = 1 + 1/2 + 1/3 + … + 1/50.
Expected Output:
Value of S: 4.50
Click me to see the solution

46. Compute series sum S=1+3/2+5/4+7/8

Write a C program to calculate the value of S where S = 1 + 3/2 + 5/4 + 7/8.
Expected Output:
Value of series: 4.62
Click me to see the solution

47. Find all divisors of a given integer

Write a C program that finds all the divisors of an integer.
Test Data:
Input an integer: 45
Expected Output:
All the divisor of 45 are:
1
3
5
9
15
45
Click me to see the solution

48. Replace negatives and zeros in an array with 100, then print

Write a C program that reads and prints the elements of an array of length 7. Before printing, replace every negative number, zero, with 100.
Test Data:
Input the 5 members of the array:
25
45
35
65
15

Expected Output:
Array values are:
n[0] = 25
n[1] = 45
n[2] = 35
n[3] = 65
n[4] = 15
Click me to see the solution

49. Populate an array where each element is triple the previous

Write a C program to read and print the elements of an array with length 7. Before printing, insert the triple of the previous position, starting from the second position.
For example, if the first number is 2, the array numbers must be 2, 6, 18, 54 and 162
Test Data:
Input the first number of the array: 5
Expected Output:
n[0] = 5
n[1] = 15
n[2] = 45
n[3] = 135
n[4] = 405
Click me to see the solution

50. Print positions and values of elements in an array < 5

Write a C program to read an array of length 5 and print the position and value of the array elements of value less than 5.
Test Data:
Input the 5 members of the array:
15
25
4
35
40
Expected Output:
A[2] = 4.0
Click me to see the solution

51. Reverse array elements by swapping positions

Write a C program to read an array of length 6, change the first element by the last, the second element by the fifth and the third element by the fourth. Print the elements of the modified array.
Test Data:
Input the 5 members of the array:
15
20
25
30
35

Expected Output:
array_n[0] = 35
array_n[1] = 30
array_n[2] = 25
array_n[3] = 20
array_n[4] = 15
Click me to see the solution

52. Find the smallest element in an array and its position

Write a C program to read an array of length 6 and find the smallest element and its position.
Test Data:
Input the length of the array: 5 Input the array elements:
25
35
20
14
45
Expected Output:
Smallest Value: 14
Position of the element: 3
Click me to see the solution

53. Calculate simple interest (P, R, T)

Write a C program that accepts the principle, rate of interest, and time and calculates simple interest.
Test Data:
Input Data: p = 10000, r = 10% , t = 12 year
Expected Output:
Input principle, Rate of interest & time to find simple interest:
Simple interest = 12000
Click me to see the solution

54. Convert distance from centimeters to inches

Write a C program that accepts a distance in centimeters and prints the corresponding value in inches.
Test Data:
Input Data: 500cms
Input the distance in cm:
Distance of 500.00 cms is = 196.85 inches
Click me to see the solution

55. Swap two numbers without a temporary variable

Write a C program that swaps two numbers without using a third variable.
Input value for x & y:
Before swapping the value of x & y: 5 7
After swapping the value of x & y: 7 5
Click me to see the solution

56. Left-shift an integer by two bits

Write a C program to shift given data by two bits to the left.
Input value : 2
Read the integer from keyboard-
Integer value = 2
The left shifted data is = 16
Click me to see the solution

57. Reverse the digits of a number

Write a C program to reverse and print a given number.
Input a number:
The original number = 234
The reverse of the said number = 432
Click me to see the solution

58. Find the difference between max and min of 4 numbers

Write a C program that accepts 4 real numbers from the keyboard and prints out the difference between the maximum and minimum values of these four numbers.
Input four numbers: 1.54 1.236 1.3625 1.002
Difference is 0.5380
Click me to see the solution

59. Calculate the sum of the series 1+1/2+1/3+...+1/n

Write a C program to display the sum of series 1 + 1/2 + 1/3 + ………. + 1/n.
Input any number: 1 + 1/0
Sum = 1/0
Click me to see the solution

60. Enumerate and display integer values for the days of the week

Write a C program to create enumerated data types for 7 days and display their values in integer constants.
Sun = 0
Mon = 1
Tue = 2
Wed = 3
Thu = 4
Fri = 5
Sat = 6
Click me to see the solution

61. Calculate and display sin⁡(1x)\sin(\frac{1}{x})sin(x1) for a real number xxx

Write a C program that accepts a real number x and prints out the corresponding value of sin(1/x) using 4-decimal places.
Input value of x: .6235
Value of sin(1/x) is 0.9995
Click me to see the solution

62. Compute the sum of the digits of an integer less than 500

Write a C program that accepts a positive integer less than 500 and prints out the sum of the digits of this number.
Input a positive number less than 500:
Sum of the digits of 347 is 14
Click me to see the solution

63. Sum the series 1^4+2^4+4^4+...+m^4

Write a C program that accepts a positive integer n less than 100 from the user. It prints out the sum of 1⁴ + 2⁴ + 4⁴ + 7⁴ + 11⁴ + • • • + m⁴. In this case, m is less than or equal to n. Print an appropriate message.
Input a positive number less than 100: 68
Sum of the series is 37361622
Click me to see the solution

64. Count positive integers and display their min, max, and average

Write a C program that accepts integers from the user until a zero or a negative number, displays the number of positive values, the minimum value, the maximum value, and the average value.
Input a positive integer:
Input next positive integer: 15
Input next positive integer: 25
Input next positive integer: 37
Input next positive integer: 43
Number of positive values entered is 4
Maximum value entered is 43
Minimum value entered is 15
Average value is 30.0000
Click me to see the solution

65. Print prime numbers between 1 and 200 in rows of 20

Write a C program that prints out the prime numbers between 1 and 200. The output should be such that each row contains a maximum of 20 prime numbers.
Expected output:
The prime numbers between 1 and 199 are:
2 3 5 7 11 13 17 19 23 29
31 37 41 43 47 53 59 61 67 71
73 79 83 89 97 101 103 107 109 113
127 131 137 139 149 151 157 163 167 173
179 181 191 193 197
Click me to see the solution

66. Generate 50 random numbers in [-0.5, 0.5] and save them to a file

Write a C program that generates 50 random numbers between -0.5 and 0.5 and writes them to the file rand.dat. The first line of ran.dat contains the number of random numbers, while the next 50 lines contain 50 random numbers.
50
-0.4215
0.2620
0.3065
-0.0485
.... 0.3980
0.1750
0.4780
-0.2915
0.0715
0.3565
Click me to see the solution

67. Evaluate y=xn

Write a C program to evaluate the equation y=xn when n is a non-negative integer.
Input the values of x and n: 256
x=256.000000; n=0;
x to power n=1.000000
Click me to see the solution

68. Print powers of 2

Write a C program that prints the powers of 2 table for the powers 0 to 10, both positive and negative.
=======================================
n 2 to power n 2 to power -n
=======================================
0 1 1.000000000000
1 2 0.500000000000
2 4 0.250000000000
3 8 0.125000000000
4 16 0.062500000000
5 32 0.031250000000
6 64 0.015625000000
7 128 0.007812500000
8 256 0.003906250000
9 512 0.001953125000
10 1024 0.000976562500
======================================
Click me to see the solution

69. Generate a binomial coefficient table

Write a C program to print a binomial coefficient table.
Mx 0 1 2 3 4 5 6 7 8 9 10
----------------------------------------------------------
0 1
1 1 1
2 1 2 1
3 1 3 3 1
4 1 4 6 4 1
5 1 5 10 10 5 1
6 1 6 15 20 15 6 1
7 1 7 21 35 35 21 7 1
8 1 8 28 56 70 56 28 8 1
9 1 9 36 84 126 126 84 36 9 1
10 1 10 45 120 210 252 210 120 45 10 1
----------------------------------------------------------
Click me to see the solution

70. Display alphabet letters with their ASCII codes

Write a C program to print the alphabet set in decimal and character form.
[65-A] [66-B] [67-C] [68-D] [69-E] [70-F] [71-G] [72-H] [73-I] [74-J] [75-K] [76-L] [77-M] [78-N] [79-O] [80-P] [81-Q] [82-R] [83-S] [84-T] [85-U] [86-V] [87-W] [88-X] [89-Y]
[90-Z] [97-a] [98-b] [99-c] [100-d] [101-e] [102-f] [103-g] [104-h] [105-i] [106-j] [107-k] [108-l] [109-m] [110-n] [111-o] [112-p] [113-q] [114-r] [115-s] [116-t] [117-u] [118-v]
[119-w] [120-x] [121-y] [122-z]
Click me to see the solution

71. Copy a string into another and count its characters

Write a C program to copy a given string into another and count the number of characters copied.
Input a string
Original string: w3resource
Number of characters = 10
Click me to see the solution

72. Remove a negative sign from a number

Write a C program to remove any negative sign in front of a number.
Input a value (negative):
Original value = -253
Absolute value = 253
Click me to see the solution

73. Check if the first integer is a multiple of the second

Write a C program that reads two integers and checks whether the first integer is a multiple of the second integer.
Sample Input: 9 3
Sample Output:
Input the first integer : Input the second integer:
9 is a multiple of 3.
Click me to see the solution

74. Display integer equivalents for all letters (a–z, A–Z)

Write a C program to display the integer equivalents of letters (a-z, A-Z).
Sample Output:
List of integer equivalents of letters (a-z, A-Z).
==================================================
97 98 99 100 101 102
103 104 105 106 107 108
109 110 111 112 113 114
115 116 117 118 119 120
121 122 32 65 66 67
68 69 70 71 72 73
74 75 76 77 78 79
80 81 82 83 84 85
86 87 88 89 90
Click me to see the solution

75. Separate the digits of a 7-digit number with spaces

Write a C program that accepts a seven-digit number, separates the number into its individual digits, and prints the digits separated from one another by two spaces each.
Sample Input: 2345678
Input a seven digit number:
Output: 2 3 4 5 6 7 8
Click me to see the solution

76. Print squares and cubes of numbers from 0 to 20

Write a C program to calculate and print the squares and cubes of the numbers from 0 to 20. It uses tabs to display them in a table of values.
Sample Output:
Number Square Cube
=========================
0 0 0
1 1 1
2 4 8
3 9 27
.....
18 324 5832
19 361 6859
20 400 8000
Click me to see the solution

77. Compute simple interest

Write a C program that accepts principal amount, rate of interest and days for a loan and calculates the simple interest for the loan, using the following formula.
interest = principal * rate * days / 365.
Sample Input:
10000
.1
365
0
Sample Output:
Input loan amount (0 to quit): Input interest rate: Input term of the loan in days: The interest amount is $1000.00
Input loan principal_amt (0 to quit):
Click me to see the solution

78. Demonstrate predecrementing vs postdecrementing

Write a C program to demonstrate the difference between predecrementing and postdecrementing using the decrement operator --.
Sample Output:
Predecrementing:
x = 10
x-- = 10
x = 9
Click me to see the solution

79. Generate a table with x,x+2,x+4 using loops

Write a C program using looping to produce the following table of values.
Sample Output:

x       x+2     x+4     x+6
--------------------------------
1       3       5       7
4       6       8       10
7       9       11      13
10      12      14      16
13      15      17      19

80. Print a filled square of size nnn using #

Write a C program that reads the side (side sizes between 1 and 10 ) of a square and prints square using hash (#) character.
Sample Input: 10
Sample Output:

Input the size of the square: 
 # # # # # # # # # #
 # # # # # # # # # #
 # # # # # # # # # #
 # # # # # # # # # #
 # # # # # # # # # #
 # # # # # # # # # #
 # # # # # # # # # #
 # # # # # # # # # #
 # # # # # # # # # #
 # # # # # # # # # #

81. Print a hollow square of size nnn using #

Write a C program that reads the side (side sizes between 1 and 10 ) of a square and prints a hollow square using the hash (#) character.
Sample Input: 10
Sample Output:

Input the size of the square: 
##########
#        #
#        #
#        #
#        #
#        #
#        #
#        #
#        #
##########

82. Check if a 5-digit integer is a palindrome

Write a C program that reads a five-digit integer and determines whether or not it's a palindrome.
Sample Input: 33333
Sample Output:

Input a five-digit number: 33333 is a palindrome.

83. Count occurrences of the digit 3 in a number

Write a C program that reads an integer (7 digits or fewer) and counts the number of 3s in the given number.
Sample Input: 538453
Sample Output:

Input a number: The number of threes in the said number is 2

84. Calculate the average of integers until 888 is entered

Write a C program to calculate and print the average of some integers. Accept all the values preceding 888.
Sample Input:12
15
24
888
Sample Output:

Input each number on a separate line (888 to exit):

The average value of the said numbers is 17.000000

85. Print Roman numeral equivalents for numbers 1 to 50

Write a C program to print a table of all the Roman numeral equivalents of decimal numbers in the range 1 to 50.
Sample Output:

Decimal  Roman
number   numeral
-------------------
1        I
2        II
3        III
4        IV
.....
98        LXXXXVIII
99        LXXXXIX
100        C

86. Display sizes and ranges of C's data types

Write a C program to display the sizes and ranges for each of C's data types.
Sample Output:

Size of C data types:

Type               Bytes

--------------------------------
char                 1
int8_t               1
unsigned char        1
uint8_t              1
short                2
int16_t              2
uint16t              2
int                  4
unsigned             4
long                 8
unsigned long        8
int32_t              4
uint32_t             4
long long            8
int64_t              8
unsigned long long   8
uint64_t             8
float                4
double               8
long double          16
_Bool                1

87. Print the min and max values for all C data types

Write a C program to display the minimum and maximum values for each of C's data types.
Sample Output:

Ranges for integer data types in C

------------------------------------------------------------
int8_t                    -128                   127
int16_t                 -32768                 32767
int32_t            -2147483648            2147483647
int64_t   -9223372036854775808   9223372036854775807
uint8_t                      0                   255
uint16_t                     0                 65535
uint32_t                     0            4294967295
uint64_t                     0  18446744073709551615

============================================================

Ranges for real number data types in C

------------------------------------------------------------
float          1.175494e-38    3.402823e+38
double        2.225074e-308   1.797693e+308
long double  3.362103e-4932  1.189731e+4932

88. Generate an extended ASCII table (codes 32–255)

Write a C program to create an extended ASCII table. Print the ASCII values 32 through 255.
Sample Output:

|---------------------------------------------------------------------------------------------------------|
|extended ASCII table - excluding control characters                                                      |
|   Ch Dec  Hex  |  Ch Dec  Hex   | Ch Dec  Hex | Ch Dec  Hex  | Ch Dec  Hex  | Ch Dec  Hex | Ch Dec  Hex |
|----------------|----------------|-------------|--------------|--------------|-------------|-------------|
|   har  32 0x20 |  @har  64 0x40 |  `  96 0x60 |  � 128 0x80 |  � 160 0xa0 |  � 192 0xc0 |  � 224 0xe0 |
|  !har  33 0x21 |  Ahar  65 0x41 |  a  97 0x61 |  � 129 0x81 |  � 161 0xa1 |  � 193 0xc1 |  � 225 0xe1 |
|  "har  34 0x22 |  Bhar  66 0x42 |  b  98 0x62 |  � 130 0x82 |  � 162 0xa2 |  � 194 0xc2 |  � 226 0xe2 |
|  #har  35 0x23 |  Char  67 0x43 |  c  99 0x63 |  � 131 0x83 |  � 163 0xa3 |  � 195 0xc3 |  � 227 0xe3 |
|  $har  36 0x24 |  Dhar  68 0x44 |  d 100 0x64 |  � 132 0x84 |  � 164 0xa4 |  � 196 0xc4 |  � 228 0xe4 |
|  %har  37 0x25 |  Ehar  69 0x45 |  e 101 0x65 |  � 133 0x85 |  � 165 0xa5 |  � 197 0xc5 |  � 229 0xe5 |
|  &har  38 0x26 |  Fhar  70 0x46 |  f 102 0x66 |  � 134 0x86 |  � 166 0xa6 |  � 198 0xc6 |  � 230 0xe6 |
|  'har  39 0x27 |  Ghar  71 0x47 |  g 103 0x67 |  � 135 0x87 |  � 167 0xa7 |  � 199 0xc7 |  � 231 0xe7 |
|  (har  40 0x28 |  Hhar  72 0x48 |  h 104 0x68 |  � 136 0x88 |  � 168 0xa8 |  � 200 0xc8 |  � 232 0xe8 |
|  )har  41 0x29 |  Ihar  73 0x49 |  i 105 0x69 |  � 137 0x89 |  � 169 0xa9 |  � 201 0xc9 |  � 233 0xe9 |
|  *har  42 0x2a |  Jhar  74 0x4a |  j 106 0x6a |  � 138 0x8a |  � 170 0xaa |  � 202 0xca |  � 234 0xea |
|  +har  43 0x2b |  Khar  75 0x4b |  k 107 0x6b |  � 139 0x8b |  � 171 0xab |  � 203 0xcb |  � 235 0xeb |
|  ,har  44 0x2c |  Lhar  76 0x4c |  l 108 0x6c |  � 140 0x8c |  � 172 0xac |  � 204 0xcc |  � 236 0xec |
|  -har  45 0x2d |  Mhar  77 0x4d |  m 109 0x6d |  � 141 0x8d |  � 173 0xad |  � 205 0xcd |  � 237 0xed |
|  .har  46 0x2e |  Nhar  78 0x4e |  n 110 0x6e |  � 142 0x8e |  � 174 0xae |  � 206 0xce |  � 238 0xee |
|  /har  47 0x2f |  Ohar  79 0x4f |  o 111 0x6f |  � 143 0x8f |  � 175 0xaf |  � 207 0xcf |  � 239 0xef |
|  0har  48 0x30 |  Phar  80 0x50 |  p 112 0x70 |  � 144 0x90 |  � 176 0xb0 |  � 208 0xd0 |  � 240 0xf0 |
|  1har  49 0x31 |  Qhar  81 0x51 |  q 113 0x71 |  � 145 0x91 |  � 177 0xb1 |  � 209 0xd1 |  � 241 0xf1 |
|  2har  50 0x32 |  Rhar  82 0x52 |  r 114 0x72 |  � 146 0x92 |  � 178 0xb2 |  � 210 0xd2 |  � 242 0xf2 |
|  3har  51 0x33 |  Shar  83 0x53 |  s 115 0x73 |  � 147 0x93 |  � 179 0xb3 |  � 211 0xd3 |  � 243 0xf3 |
|  4har  52 0x34 |  Thar  84 0x54 |  t 116 0x74 |  � 148 0x94 |  � 180 0xb4 |  � 212 0xd4 |  � 244 0xf4 |
|  5har  53 0x35 |  Uhar  85 0x55 |  u 117 0x75 |  � 149 0x95 |  � 181 0xb5 |  � 213 0xd5 |  � 245 0xf5 |
|  6har  54 0x36 |  Vhar  86 0x56 |  v 118 0x76 |  � 150 0x96 |  � 182 0xb6 |  � 214 0xd6 |  � 246 0xf6 |
|  7har  55 0x37 |  Whar  87 0x57 |  w 119 0x77 |  � 151 0x97 |  � 183 0xb7 |  � 215 0xd7 |  � 247 0xf7 |
|  8har  56 0x38 |  Xhar  88 0x58 |  x 120 0x78 |  � 152 0x98 |  � 184 0xb8 |  � 216 0xd8 |  � 248 0xf8 |
|  9har  57 0x39 |  Yhar  89 0x59 |  y 121 0x79 |  � 153 0x99 |  � 185 0xb9 |  � 217 0xd9 |  � 249 0xf9 |
|  :har  58 0x3a |  Zhar  90 0x5a |  z 122 0x7a |  � 154 0x9a |  � 186 0xba |  � 218 0xda |  � 250 0xfa |
|  ;har  59 0x3b |  [har  91 0x5b |  { 123 0x7b |  � 155 0x9b |  � 187 0xbb |  � 219 0xdb |  � 251 0xfb |
|  <har  60 0x3c |  \har  92 0x5c |  | 124 0x7c |  � 156 0x9c |  � 188 0xbc |  � 220 0xdc |  � 252 0xfc |
|  =har  61 0x3d |  ]har  93 0x5d |  } 125 0x7d |  � 157 0x9d |  � 189 0xbd |  � 221 0xdd |  � 253 0xfd |
|  >har  62 0x3e |  ^har  94 0x5e |  ~ 126 0x7e |  � 158 0x9e |  � 190 0xbe |  � 222 0xde |  � 254 0xfe |
|  ?har  63 0x3f |  _har  95 0x5f |DEL 127 0x7f |  � 159 0x9f |  � 191 0xbf |  � 223 0xdf |  � 255 0xff |

89. Compute (x+y+z) for integers in valid range

Write a C programming to calculate (x + y + z) for each pair of integers x, y and z where -2^31 <= x, y, z<= 2^31-1.
Sample Output:

Result: 140733606875472

90. List all prime palindromes between two given numbers

Write a C program to find all prime palindromes in the range of two given numbers x and y (5 <= x<y<= 1000,000,000).
A number is called a prime palindrome if the number is both a prime number and a palindrome.
Sample Output:

Input two numbers (separated by a space):
List of prime palindromes:
0
1

91. Find the angle between the clock's hour and minute hands

Write a C program to find the angle between (12:00 to 11:59) the hour hand and the minute hand of a clock. The hour hand and the minute hand are always between 0 and 180 degrees.
For example, when it's 12 o'clock, the angle of the two hands is 0 while 3:00 is 45 degrees and 6:00 is 180 degrees.
Sample Output:

Input hour(h) and minute(m) (separated by a space):
3 0
At 3:00 the angle is 90.0 degrees.
Input hour(h) and minute(m) (separated by a space):
6 15
The angle is 90.0 degrees at 6:15.
Input hour(h) and minute(m) (separated by a space):
12 0
At 12:00 the angle is 0.0 degrees.

92. Get the last nonzero digit of a factorial

Write a C program to find the last non-zero digit of the factorial of a given positive integer.
For example for 5!, the output will be "2" because 5! = 120, and 2 is the last nonzero digit of 120
Sample Output:

Input a positive number:
The last non-zero digit of the said factorial:
0

93. Check if a number is "nearly prime"

Write a C program to check if a given number is nearly prime number or not.
Nearly prime numbers are a positive integer which is equal to the product of two prime numbers.
Sample Output:

It is not a Nearly prime number.

94. Calculate BMI and display the category

Write a C program to calculate body mass index and display the grade.
Sample Output:

Input the weight: 65
Input the height: 5.6
BMI = 2.072704

Grade: Under 

95. Print Fahrenheit-Celsius conversion tables (0–150°C)

Write a C program to print the corresponding Fahrenheit to Celsius and Celsius to Fahrenheit.
Both cases initial tempratue = 0⁰, maximum temperature = 150⁰ and step 10⁰
Sample Output:

Celsius to Fahrenheit
---------------------
Celsius   Fahrenheit
   0.0 	     32.0
  10.0 	     50.0
  20.0 	     68.0
  30.0 	     86.0
....
 120.0 	    248.0
 130.0 	    266.0
 140.0 	    284.0
 150.0 	    302.0


Fahrenheit to Celsius
---------------------
Fahrenheit  Celsius
   0.0 	    -17.8
  10.0 	    -12.2
  20.0 	     -6.7
  30.0 	     -1.1
  40.0 	      4.4
  50.0 	     10.0
 ...
 120.0 	     48.9
 130.0 	     54.4
 140.0 	     60.0
 150.0 	     65.6

96. Count blanks, tabs, and newlines in a text input

Write a C program to count blanks, tabs, and newlines in input text.
Sample Output:

Number of blanks, tabs, and newlines:
Input few words/tab/newlines
The quick
brown fox jumps
over the lazy dog
^Z
blank=7,tab=2,newline=3

97. Count characters, words, and lines in a given string

Write a C program that accepts a string and counts the number of characters, words and lines.
Sample Output:

Input a string and get number of charcters, words and lines:
The quick brown fox jumps over the lazy dog
^Z

Number of Characters = 44
Number of words = 9
Number of lines = 1

98. Print each word of input text on a new line

Write a C program that accepts some text from the user and prints each word of that text on a separate line.
Sample Output:

Input some text:
The quick brown fox jumps over the lazy dog
The
quick
brown
fox
jumps
over
the
lazy
dog

99. Create a histogram for input integer values

Write a C program that takes some integer values from the user and prints a histogram.
Sample Output:

Input number of histogram bar (Maximum 10):
4
Input the values between 0 and 10 (separated by space):
9
7
4
3


Histogram:
#########
#######
####
###

100. Convert a currency value into notes and coins

Write a C program to convert a currency value (floating point with two decimal places) to the number of coins and notes.
Sample Output:

Input the currency value (floating point with two decimal places):
10357.75

Currency Notes:
100 number of Note(s): 103
50 number of Note(s): 1
5 number of Note(s): 1
2 number of Note(s): 1

Currency Coins:
.50 number of Coin(s): 1
.25 number of Coin(s): 1

101. Find range of a number from four given ranges

There are three given ranges. Write a C program that reads a floating-point number and finds the range where it belongs from four given ranges.
Sample Output:

Input a number: 87
Range (80,100]

102. Sort three integers and print both original and sorted order

Write a C program that reads three integers and sorts the numbers in ascending order. Print the original numbers and the sorted numbers.
Sample Output:

Input 3 integers: 17
-5
25

---------------------------
Original numbers: 17, -5, 25
Sorted numbers: -5, 17, 25

103. Check if two integers are multiples of each other

Write a C program that takes two integers and tests whether they are multiplied or not.
In science, a multiple is the product of any quantity and an integer. In other words, for the quantities a and b, we say that b is a multiple of a if b = na for some integer n, which is called the multiplier. If a is not zero, this is equivalent to saying that b/a is an integer.
Sample Output:

Input two integers:
3
9
Multiplies

104. Revise an item's price based on a price table

Write a C program that reads the item's price and creates a revised price for the item, based on the item price table.
Sample Output:

Input the item price:525
New Item price: 582.75
Increased price: 57.75
Increase Percentage: 11%

105. Count positive/negative numbers and calculate their averages

Write a C program that accepts seven floating point numbers and counts the number of positive and negative numbers. Print the average of all positive and negative values with two digits after the decimal number.
Sample Output:

Input 7 numbers(int/float):
25
35.75
15
-3.5
40
35
16

6 Number of positive numbers: Average 27.79

1 Number of negative numbers: Average -3.50

106. Count even, odd, positive, and negative values from 7 integers

Write a C program that accepts 7 integer values and counts the even, odd, positive and negative values.
Sample Output:

Input 7 integers:
10
12
15
-15
26
35
17

Number of even values: 3
Number of odd values: 4
Number of positive values: 6
Number of negative values: 1

107. Print next 10 odd and even numbers after a given integer

Write a C program that prints ten consecutive odd and even numbers after accepting an integer.
Sample Output:

Input an integer number:
15

Next 10 consecutive odd numbers:
17, 19, 21, 23, 25, 27, 29, 31, 33, 35,

Next 10 consecutive even numbers:
26, 28, 30, 32, 34, 36, 38, 40, 42, 44,

108. Sum odd and even numbers between two integers

Write a C program that reads two integer values and calculates the sum of all odd numbers between them.
Sample Output:

Input the first integer number:
25
Input the second integer number (greater than first integer):
45
Sum of all odd values between 25 and 45:
385
Sum of all even values between 25 and 45:
350

109. Print squares of even and odd numbers between 1 and nnn

Write a C program to find and print the square of each even and odd value between 1 and a given number (4 < n < 101).
Sample Output:

Input a number(integer): 15

Square of each even between 1 and 15:
2^2 = 4
4^2 = 16
6^2 = 36
8^2 = 64
10^2 = 100
12^2 = 144
14^2 = 196

Square of each odd between 1 and 15:
1^2 = 1
3^2 = 9
5^2 = 25
7^2 = 49
9^2 = 81
11^2 = 121
13^2 = 169
15^2 = 225

110. Classify a number as positive/negative and odd/even, or print "Zero"

Write a C program to find the odd, even, positive and negative numbers from a given number (integer) and print a message 'Number is positive odd' or 'Number is negative odd' or 'Number is positive even' or 'Number is negative even'. If the number is 0 print "Zero".
Sample Output:

Input a number (integer):
12
Number is positive-even

111. Print numbers (1–100) leaving a remainder of 3 when divided by input

Write a C program that accepts an integer from the user and divides all numbers between 1 and 100. Print those numbers where the remainder value is 3.
Sample Output:

Input a number (integer):
65

Remainder value is 3 after divide all numbers between 1 and 100 by 65:
3
68

112. Find max value and position from 7 integers

Write a C program that reads seven integer values from the user and finds the highest value and its position.
Sample Output:

Input 6 numbers (integer values):
15
20
25
17
-8
35

Maximum value: 35
Position: 6

113. Generate and print a sequence

Write a C program to create and print the sequence of the following example.
Sample Output:

a=1      b=100
a=6      b=90
a=11     b=80
a=16     b=70
a=21     b=60
a=26     b=50
a=31     b=40
a=36     b=30
a=41     b=20
a=46     b=10
a=51     b=0

114. Sum of even numbers between two integers

Write a C program that accepts two integer values and calculates the sum of all even values between them.
Sample Output:

Input two numbers (integer values):
25
45

Sum of all even values between 25 and 45
350

Sample Output:

Input two numbers (integer values):
27
13

Sum of all even values between 27 and 13
140

115. Print sequence between two numbers and calculate its average

Write a C program that accepts a pair of numbers from the user and prints the sequence from the lowest to the highest number. Also, print the average value of the sequence.

Sample Output:

Input two pairs values (integer values):
14
25

Sequence from the lowest to highest number:
14 15 16 17 18 19 20 21 22 23 24 25
Average value of the said sequence
    19.50

Sample Output:

Input two pairs values (integer values):
35
13

Sequence from the lowest to highest number:
13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Average value of the said sequence
    24.00

116. Check if two integers are in ascending or descending order

Write a C program that accepts a pair of numbers from the user and prints "Ascending order" if the two numbers are in ascending order, otherwise prints, "Descending order".

Sample Output:

Input two pairs values (integer values):
12
35
Ascending order

Sample Output:

Input two pairs values (integer values):
65
25
Descending order

117. Divide two integers and print result or "Division not possible"

Write a C program that reads two integers and divides the first number by second, print the result of this division with two digits after the decimal point and prints “Division not possible..!” if the division is not possible.

Sample Output:

Input two integer values:
75
5
Result: 15.00

118. Calculate the average of marks from 5 subjects

Write a C program that reads five subject marks (0-100) of a student and calculates the average of these marks.

Sample Output:

Input five subject marks(0-100):
75
84
56
98
68
Average marks = 76.20

119. Sum numbers between two integers, skipping those divisible by 7

Write a C program to calculate the sum of all numbers between two given numbers (inclusive) not divisible by 7.

Sample Output:

Input two numbers(integer):
25
5
Sum of all numbers between said numbers (inclusive) not divisible by 7:
273

Sample Output:

Input two numbers(integer):
6
36
Sum of all numbers between said numbers (inclusive) not divisible by 7:
546

120. Print sequence from 1 to nnn separated by commas

Write a C program to print a sequence from 1 to a given (integer) number, inserting a comma between these numbers. There will be no comma after the last character.

Sample Output:

Input a number(integer):
25
Sequence:
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25

121. Find and print all divisors of an integer

Write a C program that reads an integer and finds all the divisors of the said integer.

Sample Output:

Input a number (integer value):
35

All positive divisors of 35
1
5
7
35

122. Compute sum of nnn even numbers starting from mmm

Write a C program that reads two integers m, n and computes the sum of n even numbers starting from m.

Sample Output:

Input two integes (m, n):
20
60

Sum of 60 even numbers starting from 20:
4740

123. Compute sum of nnn odd numbers starting from mmm

Write a C program that reads two integers m, n and computes the sum of n odd numbers starting from m.

Sample Output:

Input two integes (m, n):
65
5

Sum of 5 odd numbers starting from 65:
345

124. Replace negative/null elements of an array with 1

Write a C program that reads an array of integers (length 7), replaces every negative or null element with 1 and prints the array elements.

Sample Output:

Input 7 array elements:
15
12
-7
25
0
27
53

Array elements:
array_nums[0] = 15
array_nums[1] = 12
array_nums[2] = 1
array_nums[3] = 25
array_nums[4] = 1
array_nums[5] = 27
array_nums[6] = 53

125. Replace first element of array and double subsequent values

Write a C program that reads an array of integers (length 7), and replaces the first element of the array by a given number and replaces each subsequent position of the array by the double value of the previous.

Sample Output:

Input the first element of the array:
5

Array elements:
array_nums[0] = 5
array_nums[1] = 10
array_nums[2] = 20
array_nums[3] = 40
array_nums[4] = 80
array_nums[5] = 160
array_nums[6] = 320

126. Print positions of array elements

Write a C program that reads an array (length 7) and prints all array positions that store a value less than or equal to 0.

Sample Output:

Input 7 array elements:
15
23
37
65
20
-7
65

Array positions that store a value less or equal to 0:
array_nums[5] = -7.0

127. Reverse the first and last elements of an array

Write a C program that reads an array of integers (length 8), replaces the 1st element with the 8^th, the 2^nd with the 7^th and so on. Print the final array.

Sample Output:

Input 8 array elements:
25
35
17
-5
29
45
60
65

Modified array:
array_nums[0] = 65
array_nums[1] = 60
array_nums[2] = 45
array_nums[3] = 29
array_nums[4] = -5
array_nums[5] = 17
array_nums[6] = 35
array_nums[7] = 25

128. Fill array with repeated values up to a given number

Write a C program that reads an array of integers (length 10), fills it with numbers from o to a (given number) n – 1 repeatedly, where 2 ≤ n ≤ 10.

Sample Output:

Input an integer (2-10)
8
array_nums[0] = 0
array_nums[1] = 1
array_nums[2] = 2
array_nums[3] = 3
array_nums[4] = 4
array_nums[5] = 5
array_nums[6] = 6
array_nums[7] = 7
array_nums[8] = 0
array_nums[9] = 1

129. Replace array elements with one-third of the previous

Write a C program that reads an array (length 10), and replaces the first element of the array by a given number and replaces each subsequent position of the array by one-third the value of the previous.

Sample Output:

Input an integer (2-10)
8
array_nums[0] = 0
array_nums[1] = 1
array_nums[2] = 2
array_nums[3] = 3
array_nums[4] = 4
array_nums[5] = 5
array_nums[6] = 6
array_nums[7] = 7
array_nums[8] = 0
array_nums[9] = 1

130. Find smallest value and its position in an array

Write a C program to create an array of length n and fill the array elements with integer values. Find the smallest value and its position in the array.

Sample Output:

Input a number:
35

Array elements:
array_nums[0] = 35.0000
array_nums[1] = 11.6667
array_nums[2] = 3.8889
array_nums[3] = 1.2963
array_nums[4] = 0.4321
array_nums[5] = 0.1440
array_nums[6] = 0.0480
array_nums[7] = 0.0160
array_nums[8] = 0.0053
array_nums[9] = 0.0018

131. Check if a string ends with another string

Write a C program that accepts two strings and checks whether the second string is present in the last part of the first string.

Sample Output:

Input the first string:
abcdef
Input the second string:
ef
Is second string present in the last part of the first string?
Present!

132. Find heights of top three tallest buildings

Write a C program to find the heights of the top three buildings in descending order from eight given buildings.
Input:
0 <= height of building (integer) <= 10,000

Sample Output:

Input heights(integer values) of the top eight buildings:
25
15
45
22
35
18
95
65

Heights of the top three building:
95
65
45

133. Sum two integers and count digits in the result

Write a C program to calculate the sum of two given integers and count the number of digits in the sum value.

Sample Output:

Input two integer values:
68
75

Number of digits of the sum value of the said numbers:
3

134. Check if three sides form a right triangle

Write a C program to check whether the three given lengths (integers) of three sides of a triangle form a right triangle or not. Print "Yes" if the given sides form a right triangle otherwise print "No".
Input:
Integers separated by a single space.
1 <= length of the side <= 1,000

Sample Output:

Input the three sides of a trainagel:
12
11
13
It is not a right angle triangle!

135. Count combinations of four digits summing to nnn

Write a C program that reads an integer n and finds the number of combinations of a, b, c and d (0 ≤ a, b, c, d ≤ 9) where (a + b + c + d) will be equal to n.
Input:
n (1 <= n <= 50)

Sample Output:

Input a number:
5

a + b + c + d = n
0, 0, 0, 5
0, 0, 1, 4
....
4, 0, 1, 0
4, 1, 0, 0
5, 0, 0, 0

Total number of combinations:
56

136. Find all prime numbers ≤n\leq n≤n

Write a C program to find prime numbers that are less than or equal to a given integer.
Input:
n (1 <= n <= 999,999)

Sample Output:

Input a number:
123
Number of prime numbers which are less than or equal to 123
30

137. Check if a point lies within a triangle

Write a C program to check if a point (x, y) is within a triangle or not. Three points make up a triangle.
Input:
x1,y1,x2,y2,x3,y3,xp,yp separated by a single space

Sample Output:

Input three points to form a triangle:
x1 y1 z1

Input the point to check it is inside the triangle or not:
The point is outside the triangle!

138. Determine if two lines are parallel

Write a C program to test whether two lines are parallel or not. The four points are P(x1, y1), Q(x2, y2), R(x3, y3) and S(x4, y4), check PQ and RS are parallel are not.
Input:
−100 <= x1, y1, x2, y2, x3, y3, x4, y4 <= 100
Each value is a real number with at most 5 digits after the decimal point.

Sample Output:

Input P(x1,y1):
5
7

Input P(x2,y2):
3
6

Input P(x3,y3):
8
9

Input P(x4,y4):
5
6

PQ and RS are not parallel!

139. Maximum sum of a contiguous subsequence in an array

Write a C program to find the maximum sum of a contiguous subsequence from a given sequence of numbers a1, a2, a3, ... an ( n = number of terms in the sequence).
Input:
You can assume that 1 <= n <= 500 and -10000 <= ai <= 10000.

Sample Output:

Input number of terms in the sequence:
5

Input the terms of the said sequence:
3
2
6
-7
8
Maximum sum of a contiguous subsequence:
12

140. Find the most frequently occurring number in a sequence

Write a C program that reads a sequence of integers and finds the element that occurs most frequently.

Sample Output:

Input the terms of the sequence:
5
2
4
6
8
10
^Z
Mode values of the said sequence in ascending order:
2
4
5
6
8
10

141. Count digit combinations that sum to sss

Write a C program that reads n digits (given) chosen from 0 to 9 and prints the number of combinations where the sum of the digits equals another given number (s). Do not use the same digits in a combination.
For example, the combinations where n = 3 and s = 6 are as follows:
1 + 2 + 3 = 6
0 + 1 + 5 = 6
0 + 2 + 4 = 6

Sample Output:

Input the number:
3

Sum of the digits:
6
Number of combinations: 3

142. Check if parallelogram is a rectangle or rhombus

Write a C program that reads the two adjoining sides and the diagonal of a parallelogram and checks whether the parallelogram is a rectangle or a rhombus.
Input:
Two adjoined sides and the diagonal.
1 <= ai, bi, ci <= 1000, ai + bi > ci

Sample Output:

Input two adjoined sides of the parallelogram:
3
4

Input the diagonal of the parallelogram:
5

This is a rectangle.

Sample Output:

Input two adjoined sides of the parallelogram:
5
5

Input the diagonal of the parallelogram:
7

This is a rhombus.

143. Find difference between largest and smallest integers from digits

Write a C program to find the difference between the largest integer and the smallest integer, which are created by 8 numbers from 0 to 9. The number that can be rearranged shall start with 0 as in 00135668.
Input:
Data is a sequence of 8 numbers (digits from 0 to 9).
Output:
The difference between the largest integer and the smallest integer.

Sample Output:

Input an integer created by 8 numbers (0 to 9):
25346879

The difference between the largest integer and the smallest integer.
98765432 - 23456789 = 75308643

144. Maximum regions formed by nnn straight lines

Write a C program to create the maximum number of regions obtained by drawing n given straight lines.
Input:
(1 ≤ n ≤ 10,000).

Sample Output:

Input number of straight lines:
2
Maximum number of regions obtained by drawing 2 given straight lines:
4

145. Sum numerical values embedded in a sentence

Write a C program to sum all numerical values (positive integers) embedded in a sentence.
Input:
Sentences with positive integers are given over multiple lines. Each line is a character string containing one-byte alphanumeric characters, symbols, spaces, or an empty line. However the input is 80 characters or less per line and the sum is 10,000 or less.

Sample Output:

Input Sentences with positive integers:
5littleJackand2mouse.

Sum of all numerical values embedded in a sentence:
7

146. Extract words of 3 to 6 characters from a sentence

Write a C program to extract words of 3 to 6 characters length from a given sentence not more than 1024 characters.
Input:
English sentences consisting of delimiters and alphanumeric characters are given on one line.

Sample Output:

English sentences consisting of delimiters and alphanumeric characters on one line:
w3resource.com

Extract words of 3 to 6 characters length from the said sentence:
com

147. Count combinations satisfying p+q+r+s=n

Write a C program to find the number of combinations that satisfy p + q + r + s = n where n is a given number <= 4000 and p, q, r, s are between 0 and 1000.

Sample Output:

Input a positive integer:
25

Number of combinations of p,q,r,s:
3276

148. Add rows and columns of a matrix

Write a C program, which adds up columns and rows of given table as shown in the following figure.

Input:
n (the size of row and column of the given table)
1st row of the table
2nd row of the table
:
:
n th row of the table
The input ends with a line consisting of a single 0.

Sample Output:

Input number of rows/columns:
4
Input the cell value

Row 0 input cell values
25
69
51
26

Row 1 input cell values
68
35
29
54

Row 2 input cell values
54
57
45
63

Row 3 input cell values
61
68
47
59

Result:
   25   69   51   26  171
   68   35   29   54  186
   54   57   45   63  219
   61   68   47   59  235
  208  229  172  202  811

149. Group words by page numbers

Write a C program that reads a list of pairs of a word and a page number, and prints the word and a list of the corresponding page numbers.
Input:
word page_number
Output:
word
a_list_of_the_page_number
word
a_list_of_the_Page_number.

Sample Output:

Input pairs of a word and a page_no number:
Twinkle
65
Twinkle
55
Little
25
Star
35
^Z

Word and page_no number in alphabetical order:
Little
25
Star
35
Twinkle
55 65

150. Evaluate an arithmetic expression

Write a C program that reads an expression and evaluates it.
Input:
4
10-2*3=
8*(8+2-5)=

Sample Output:

Input an expression using +, -, *, / operators:
1+6*8-4/2
47

Sample Output:

Input an expression using +, -, *, / operators:
25/5-6*7+2
-35

Sample Output:

Input an expression using +, -, *, / operators:
9+6+(5*2)-5
20

C programming Code Editor:

More to Come !

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