# C Programming Exercises, Practice, Solution : Recursion

## C Recursion [21 exercises with solution]

1. Write a program in C to print first 50 natural numbers using recursion. Go to the editor
Expected Output :

``` The natural numbers are : 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
31  32  33  34  35  36  37  38
39  40  41  42  43  44  45  46  47
48  49  50
```

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2. Write a program in C to calculate the sum of numbers from 1 to n using recursion. Go to the editor
Test Data :
Input the last number of the range starting from 1 : 5
Expected Output :

```The sum of numbers from 1 to 5 :
15
```

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3. Write a program in C to Print Fibonacci Series using recursion. Go to the editor
Test Data :
Input number of terms for the Series (< 20) : 10
Expected Output :

``` Input number of terms for the Series (< 20) : 10
The Series are :
1  1  2  3  5  8  13  21  34  55
```

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4. Write a program in C to print the array elements using recursion. Go to the editor
Test Data :
Input the number of elements to be stored in the array :6
Input 6 elements in the array :
element - 0 : 2
element - 1 : 4
element - 2 : 6
element - 3 : 8
element - 4 : 10
element - 5 : 12
Expected Output :

```The elements in the array are : 2  4  6  8  10  12
```

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5. Write a program in C to count the digits of a given number using recursion. Go to the editor
Test Data :
Input a number : 50
Expected Output :

```The number of digits in the number is :  2
```

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6. Write a program in C to find the sum of digits of a number using recursion. Go to the editor
Test Data :
Input any number to find sum of digits: 25
Expected Output :

```The Sum of digits of 25 = 7
```

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7. Write a program in C to find GCD of two numbers using recursion. Go to the editor
Test Data :
Input 1st number: 10
Input 2nd number: 50
Expected Output :

`The GCD of 10 and 50 is: 10 `

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8. Write a program in C to get the largest element of an array using recursion. Go to the editor
Test Data :
Input the number of elements to be stored in the array :5
Input 5 elements in the array :
element - 0 : 5
element - 1 : 10
element - 2 : 15
element - 3 : 20
element - 4 : 25
Expected Output :

```Largest element of an array is: 25
```

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9. Write a program in C to reverse a string using recursion. Go to the editor
Test Data :
Input any string: w3resource
Expected Output :

```The reversed string is: ecruoser3w
```

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10. Write a program in C to find the Factorial of a number using recursion. Go to the editor
Test Data :
Input a number : 5
Expected Output :

```The Factorial of 5 is : 120
```

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11. Write a program in C to convert a decimal number to binary using recursion. Go to the editor
Test Data :
Input any decimal number : 66
Expected Output :

```The Binary value of decimal no. 66 is : 1000010
```

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12. Write a program in C to check a number is a prime number or not using recursion. Go to the editor
Test Data :
Input any positive number : 7
Expected Output :

```The number 7 is a prime number.
```

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13. Write a program in C to find the LCM of two numbers using recursion. Go to the editor
Test Data :
Input 1st number for LCM : 4
Input 2nd number for LCM : 6
Expected Output :

```The LCM of 4 and 6 :  12
```

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14. Write a program in C to print even or odd numbers in given range using recursion. Go to the editor
Test Data :
Input the range to print starting from 1 : 10
Expected Output :

```All even numbers from 1 to 10 are : 2  4  6  8  10
All odd numbers from 1 to 10 are : 1  3  5  7  9
```

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15. Write a program in C to multiply two matrix using recursion. Go to the editor
Test Data :
Input number of rows for the first matrix : 2
Input number of columns for the first matrix : 1
Input number of rows for the second matrix : 1
Input number of columns for the second matrix : 2
Input elements in the first matrix :
element - [0],[0] : 1
element - [1],[0] : 2
Input elements in the second matrix :
element - [0],[0] : 3
element - [0],[1] : 4
Expected Output :

```Here is the elements of First matrix :

1
2
Here is the elements of Second matrix :

3       4
The multiplication of two matrix is :

3       4
6       8
```

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16. Write a program in C to Check whether a given String is Palindrome or not. Go to the editor
Test Data :
Input a word to check for palindrome : mom
Expected Output :

``` The entered word is a palindrome.
```

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17. Write a program in C to calculate the power of any number using recursion. Go to the editor
Test Data :
Input the base value : 2
Input the value of power : 6
Expected Output :

```The value of 2 to the power of 6 is : 64
```

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18. Write a program in C to find the Hailstone Sequence of a given number. Go to the editor
Test Data :
Input any number (positive) to start for Hailstone Sequence : 13
Expected Output :

``` The hailstone sequence starting at 13 is :
13  40  20  10  5  16  8  4  2 1
The length of the sequence is 10.
```

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19. Write a program in C to copy One string to another using recursion. Go to the editor
Test Data :
Input the string to copy : w3resource
Expected Output :

``` The string successfully copied.

The first string is : w3resource
The copied string is : w3resource
```

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20. Write a program in C to find the first capital letter in a string using recursion. Go to the editor
Test Data :
Input a string to including one or more capital letters : testString
Expected Output :

``` The first capital letter appears in the string testString is S.
```

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21. Write a program in C for binary search using recursion. Go to the editor
Test Data :
Input the number of elements to store in the array :3
Input 3 numbers of elements in the array :
element - 0 : 25
element - 1 : 98
element - 2 : 18
Input the number to search : 18
Expected Output :

``` The search number found in the array.
```

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## Practice online

```#include <stdio.h>
int main()
{

}```

List of Exercises with Solutions :

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