# C Programming Exercises, Practice, Solution : For Loop

## C For Loop [61 exercises with solution]

[*An editor is available at the bottom of the page to write and execute the scripts.*]

**1. ** Write a program in C to display the first 10 natural numbers. Go to the editor

*Expected Output* :

1 2 3 4 5 6 7 8 9 10

Click me to see the solution

**2. ** Write a C program to compute the sum of the first 10 natural numbers. Go to the editor

*Expected Output* :

The first 10 natural number is :

1 2 3 4 5 6 7 8 9 10

The Sum is : 55

Click me to see the solution

**3. ** Write a program in C to display n terms of natural numbers and their sum. Go to the editor

Test Data : 7

*Expected Output* :

The first 7 natural number is :

1 2 3 4 5 6 7

The Sum of Natural Number upto 7 terms : 28

Click me to see the solution

**4. ** Write a program in C to read 10 numbers from the keyboard and find their sum and average. Go to the editor

Test Data :

Input the 10 numbers :

Number-1 :2

...

Number-10 :2

*Expected Output* :

The sum of 10 no is : 55

The Average is : 5.500000

Click me to see the solution

**5. ** Write a program in C to display the cube of the number up to an integer. Go to the editor

Test Data :

Input number of terms : 5

*Expected Output* :

Number is : 1 and cube of the 1 is :1

Number is : 2 and cube of the 2 is :8

Number is : 3 and cube of the 3 is :27

Number is : 4 and cube of the 4 is :64

Number is : 5 and cube of the 5 is :125

Click me to see the solution

**6. ** Write a program in C to display the multiplication table for a given integer. Go to the editor

Test Data :

Input the number (Table to be calculated) : 15

*Expected Output* :

15 X 1 = 15

...

...

15 X 10 = 150

Click me to see the solution

**7.** Write a program in C to display the multiplier table vertically from 1 to n. Go to the editor

Test Data :

Input upto the table number starting from 1 : 8

*Expected Output* :

Multiplication table from 1 to 8

1x1 = 1, 2x1 = 2, 3x1 = 3, 4x1 = 4, 5x1 = 5, 6x1 = 6, 7x1 = 7, 8x1 = 8

...

1x10 = 10, 2x10 = 20, 3x10 = 30, 4x10 = 40, 5x10 = 50, 6x10 = 60, 7x10 = 70, 8x10 = 80

Click me to see the solution

**8. ** Write a C program to display the n terms of odd natural numbers and their sum. Go to the editor

Test Data

Input number of terms : 10

*Expected Output* :

The odd numbers are :1 3 5 7 9 11 13 15 17 19

The Sum of odd Natural Number upto 10 terms : 100

Click me to see the solution

**9. ** Write a program in C to display a pattern like a right angle triangle using an asterisk. Go to the editor

The pattern like :

* ** *** ****

**10.** Write a C program to display a pattern like a right angle triangle with a number. Go to the editor

The pattern like :

1 12 123 1234

**11. ** Write a program in C to make such a pattern like a right angle triangle with a number which will repeat a number in a row. Go to the editor

The pattern like :

1 22 333 4444

**12. ** Write a program in C to make such a pattern like a right angle triangle with the number increased by 1. Go to the editor

The pattern like :

1 2 3 4 5 6 7 8 9 10

**13. ** Write a program in C to make a pyramid pattern with numbers increased by 1. Go to the editor

1 2 3 4 5 6 7 8 9 10Click me to see the solution

**14. ** Write a C program to make such a pattern as a pyramid with an asterisk. Go to the editor

* * * * * * * * * *

**15. **Write a C program to calculate the factorial of a given number. Go to the editor

Test Data :

Input the number : 5

*Expected Output* :

The Factorial of 5 is: 120

Click me to see the solution

**16. ** Write a C program to display the sum of n terms of even natural numbers. Go to the editor

Test Data :

Input number of terms : 5

*Expected Output* :

The even numbers are :2 4 6 8 10

The Sum of even Natural Number upto 5 terms : 30

Click me to see the solution

**17. ** Write a C program to make such a pattern like a pyramid with a number which will repeat the number in the same row. Go to the editor

1 2 2 3 3 3 4 4 4 4

**18. ** Write a program in C to find the sum of the series [ 1-X^2/2!+X^4/4!- .........]. Go to the editor

Test Data :

Input the Value of x :2

Input the number of terms : 5

*Expected Output* :

the sum = -0.415873

Number of terms = 5

value of x = 2.000000

Click me to see the solution

**19. ** Write a program in C to display the n terms of a harmonic series and their sum. Go to the editor

1 + 1/2 + 1/3 + 1/4 + 1/5 ... 1/n terms

Test Data :

Input the number of terms : 5

*Expected Output* :

1/1 + 1/2 + 1/3 + 1/4 + 1/5 +

Sum of Series upto 5 terms : 2.283334

Click me to see the solution

**20. ** Write a C program to display the pattern as a pyramid using asterisks, with each row containing an odd number of asterisks. Go to the editor

* *** *****

**21. **Write a program in C to display the sum of the series [ 9 + 99 + 999 + 9999 ...]. Go to the editor

Test Data :

Input the number or terms :5

*Expected Output* :

9 99 999 9999 99999

The sum of the saries = 111105

Click me to see the solution

**22. ** Write a program in C to print Floyd's Triangle. Go to the editor

1 01 101 0101 10101Click me to see the solution

**23. ** Write a program in C to find the sum of the series [x - x^3 + x^5 + ......]. Go to the editor

Test Data :

Input the value of x :3

Input number of terms : 5

*Expected Output* :

The sum is : 16.375000

Click me to see the solution

**24. ** Write a program in C to find the sum of the series [ x - x^3 + x^5 + ......]. Go to the editor

Test Data :

Input the value of x :2

Input number of terms : 5

*Expected Output* :

The values of the series:

2

-8

32

-128

512

The sum = 410

Click me to see the solution

**25. ** Write a C program that displays the n terms of square natural numbers and their sum. Go to the editor

1 4 9 16 ... n Terms

Test Data :

Input the number of terms : 5

*Expected Output* :

The square natural upto 5 terms are :1 4 9 16 25

The Sum of Square Natural Number upto 5 terms = 55

Click me to see the solution

**26. ** Write a program in C to find the sum of the series 1 +11 + 111 + 1111 + .. n terms. Go to the editor

Test Data :

Input the number of terms : 5

*Expected Output* :

1 + 11 + 111 + 1111 + 11111

The Sum is : 12345

Click me to see the solution

**27. ** Write a C program to check whether a given number is a 'Perfect' number or not. Go to the editor

Test Data :

Input the number : 56

*Expected Output* :

The positive divisor : 1 2 4 7 8 14 28

The sum of the divisor is : 64

So, the number is not perfect.

Click me to see the solution

**28. ** Write a C program to find the 'Perfect' numbers within a given number of ranges. Go to the editor

Test Data :

Input the starting range or number : 1

Input the ending range of number : 50

*Expected Output* :

The Perfect numbers within the given range : 6 28

Click me to see the solution

**29. ** Write a C program to check whether a given number is an Armstrong number or not. Go to the editor

Test Data :

Input a number: 153

*Expected Output* :

153 is an Armstrong number.

Click me to see the solution

**30. ** Write a C program to find the Armstrong number for a given range of number. Go to the editor

Test Data :

Input starting number of range: 1

Input ending number of range : 1000

*Expected Output* :

Armstrong numbers in given range are: 1 153 370 371 407

Click me to see the solution

**31. ** Write a program in C to display a pattern like a diamond. Go to the editor

* *** ***** ******* ********* ******* ***** *** *

**32. ** Write a C program to determine whether a given number is prime or not. Go to the editor

Test Data :

Input a number: 13

*Expected Output* :

13 is a prime number.

Click me to see the solution

**33. ** Write a C program to display Pascal's triangle. Go to the editor

Test Data :

Input number of rows: 5

*Expected Output* :

1 1 1 1 2 1 1 3 3 1 1 4 6 4 1Click me to see the solution

**34. ** Write a program in C to find the prime numbers within a range of numbers. Go to the editor

Test Data :

Input starting number of range: 1

Input ending number of range : 50

*Expected Output* :

The prime number between 1 and 50 are :

2 3 5 7 11 13 17 19 23 29 31 37 41 43 47

Click me to see the solution

**35. ** Write a program in C to display the first n terms of the Fibonacci series. Go to the editor

Fibonacci series 0 1 2 3 5 8 13 .....

Test Data :

Input number of terms to display : 10

*Expected Output* :

Here is the Fibonacci series upto to 10 terms :

0 1 1 2 3 5 8 13 21 34

Click me to see the solution

**36. ** Write a C program to display a such a pattern for n rows using a number that starts with 1 and each row will have a 1 as the first and last number. Go to the editor

1 121 12321Click me to see the solution

**37. ** Write a program in C to display the number in reverse order. Go to the editor

Test Data :

Input a number: 12345

*Expected Output* :

The number in reverse order is : 54321

Click me to see the solution

**38. ** Write a C program to check whether a number is a palindrome or not. Go to the editor

Test Data :

Input a number: 121

*Expected Output* :

121 is a palindrome number.

Click me to see the solution

**39. ** Write a program in C to find the number and sum of all integers between 100 and 200 which are divisible by 9. Go to the editor

*Expected Output* :

Numbers between 100 and 200, divisible by 9 :

108 117 126 135 144 153 162 171 180 189 198

The sum : 1683

Click me to see the solution

**40. ** Write a C program to display the pyramid pattern using the alphabet. Go to the editor

A A B A A B C B A A B C D C B A

**41. ** Write a program in C to convert a decimal number into binary without using an array. Go to the editor

Test Data :

Input a decimal number: 25

Binary number equivalent to said decimal number is: 0000000000000000000000000001
1001

Click me to see the solution

**42. ** Write a C program to convert a binary number into a decimal number without using array, function and while loop. Go to the editor

Test Data :

Input a binary number :1010101

*Expected Output* :

The Binary Number : 1010101

The equivalent Decimal Number : 85

Click me to see the solution

**43. ** Write a C program to find the HCF (Highest Common Factor) of two numbers. Go to the editor

Test Data :

Input 1st number for HCF: 24

Input 2nd number for HCF: 28

*Expected Output* :

HCF of 24 and 28 is : 4

Click me to see the solution

**44. ** Write a C program to find the LCM of any two numbers using HCF. Go to the editor

Test Data :

Input 1st number for LCM: 15

Input 2nd number for LCM: 20

*Expected Output* :

The LCM of 15 and 20 is : 60

Click me to see the solution

**45. ** Write a program in C to find the LCM of any two numbers. Go to the editor

Test Data :

Input 1st number for LCM: 15

Input 2nd number for LCM: 20

*Expected Output* :

The LCM of 15 and 20 is : 60

Click me to see the solution

**46. ** Write a C program to convert a binary number into a decimal number using the math function. Go to the editor

Test Data :

Input the binary number :1010100

*Expected Output* :

The Binary Number : 1010100

The equivalent Decimal Number is : 84

Click me to see the solution

**47. ** Write a C program to check whether a number is a Strong Number or not. Go to the editor

Test Data :

Input a number to check whether it is Strong number: 15

*Expected Output* :

15 is not a Strong number.

Click me to see the solution

**48. ** Write a C program to find Strong Numbers within a range of numbers. Go to the editor

Test Data :

Input starting range of number : 1

Input ending range of number: 200

*Expected Output* :

The Strong numbers are :

1 2 145

Click me to see the solution

**49. ** Write a C program to find the sum of an A.P. series. Go to the editor

Test Data :

Input the starting number of the A.P. series: 1

Input the number of items for the A.P. series: 10

Input the common difference of A.P. series: 4

*Expected Output* :

The Sum of the A.P. series are :

1 + 5 + 9 + 13 + 17 + 21 + 25 + 29 + 33 + 37 = 190

Click me to see the solution

**50. ** Write a program in C to convert a decimal number into octal without using an array. Go to the editor

Test Data :

Enter a number to convert : 79

*Expected Output* :

The Octal of 79 is 117.

Click me to see the solution

**51. ** Write a C program to convert an octal number to a decimal without using an array. Go to the editor

Test Data :

Input an octal number (using digit 0 - 7) :745

*Expected Output* :

The Octal Number : 745

The equivalent Decimal Number : 485

Click me to see the solution

**52. ** Write a C program to find the sum of the G.P. series. Go to the editor

Test Data :

Input the first number of the G.P. series: 3

Input the number or terms in the G.P. series: 5

Input the common ratio of G.P. series: 2

*Expected Output* :

The numbers for the G.P. series:

3.000000 6.000000 12.000000 24.000000 48.000000

The Sum of the G.P. series : 93.000000

Click me to see the solution

**53. ** Write a C program to convert a binary number to octal. Go to the editor

Test Data :

Input a binary number :1001

*Expected Output* :

The Binary Number : 1001

The equivalent Octal Number : 11

Click me to see the solution

**54. ** Write a program in C to convert an octal number into binary. Go to the editor

Test Data :

Input an octal number (using digit 0 - 7) :57

*Expected Output* :

The Octal Number : 57

The equivalent Binary Number : 101111

**55. ** Write a C program to convert a decimal number to hexadecimal. Go to the editor

Test Data :

Input any Decimal number: 79

*Expected Output* :

The equivalent Hexadecimal Number : 4F

Click me to see the solution

**56. ** Write a program in C to check whether a number can be expressed as the sum of two prime. Go to the editor

Test Data :

Input a positive integer: 16

*Expected Output* :

16 = 3 + 13

16 = 5 + 11

Click me to see the solution

**57. ** Write a C program to print a string in reverse order. Go to the editor

Test Data :

Input a string to reverse : Welcome

*Expected Output* :

Reversed string is: emocleW

Click me to see the solution

**58. ** Write a C program to find the length of a string without using the library function. Go to the editor

Test Data :

Input a string : welcome

*Expected Output* :

The string contains 7 number of characters.

So, the length of the string welcome is : 7

Click me to see the solution

**59. ** Write a C program to check the Armstrong number of n digits. Go to the editor

Test Data :

Input an integer : 1634

*Expected Output* :

1634 is an Armstrong number

Click me to see the solution

**60. ** Write a C program that takes user input and counts the number of characters until the end of the file. Go to the editor

Test Data :

Input characters : w3resource

*Expected Output* :

Input characters: On Linux systems and OS X EOF is CTRL+D. For Windows EOF is CTRL+Z.
Number of Characters: 10

Click me to see the solution

**61. ** Write a C program that takes input from the user and counts the number of uppercase and lowercase letters, as well as the number of other characters. Go to the editor

Test Data :

Input characters : w3resource

*Expected Output* :

Input characters: On Linux systems and OS X EOF is CTRL+D. For Windows EOF is CTRL+Z.
Uppercase letters: 0
Lowercase letters: 9
Other characters: 1

Click me to see the solution

## C Programming Code Editor:

**More to Come !**

**Do not submit any solution of the above exercises at here, if you want to contribute go to the appropriate exercise page.**

## C Programming: Tips of the Day

**C Programming - Terminate any string from given index in C language**

How to terminate any string from a given index using NULL character.

This is a simple C language trick, by using this you can terminate any string from given index by assigning NULL.

We are aware that string is terminated with NULL, if we are reading a string from the keyboard, the associated function like (scanf, fgets, gets...) inserts a NULL character at the end of the string, like these functions we can also insert NULL at any index to terminate the string.

Let suppose there is a string "Hello world" and you want to keep only "Hello" in the original string (character array) variable. You can assign NULL at the index 5 (counting from 0) and string will be terminated.

Consider this example:

#include <stdio.h> int main() { char str[]="Hello world"; printf("str before terminating: %s\n",str); //assign NULL at index 5 str[5]='\0'; printf("str after terminating: %s\n",str); return 0; }

Output:

str before terminating: Hello world str after terminating: Hello

Using user define function

#include <stdio.h> //declaration void terminate(char *str,int index); int main() { char str[]="Hello world"; printf("str before terminating: %s\n",str); //function calling terminate(str,5); printf("str after terminating: %s\n",str); return 0; } //definition void terminate(char *str,int index){ str[index]='\0'; }

Ref : https://bit.ly/37EhyeR

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