C Program for GCD of two numbers using recursion

Recursion : :

• Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.

• The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.

• Recursive functions are very useful to solve many mathematical problems, such as calculating the factorial of a number, generating Fibonacci series, etc.

Here is the source code of the C Program for GCD of two numbers using recursion. The C Program is successfully compiled and run on a Windows system. The program output is also shown below.

SOURCE CODE : :

/*  C Program for GCD of two numbers using recursion  */

#include<stdio.h>

int gcd_numbers(int ,int );

int main()
{
        int n1,n2,gcd;

        printf("Enter 1st number :: ");
        scanf("%d",&n1);
        printf("\nEnter 2nd number :: ");
        scanf("%d",&n2);

        gcd=gcd_numbers(n1,n2);

        printf("\nGCD of two numbers [ %d and %d ] is :: %d\n",n1,n2,gcd);
}


int gcd_numbers(int x,int y)
{
        while(x!=y)
    {
                if(x>y)
                        return gcd_numbers(x-y,y);

                else
                        return gcd_numbers(x,y-x);

        }

        return x;
}

OUTPUT : :

/*  C Program for GCD of two numbers using recursion  */

Enter 1st number :: 6

Enter 2nd number :: 32

GCD of two numbers [ 6 and 32 ] is :: 2

Process returned 0

Above is the source code for C Program for GCD of two numbers using recursion which is successfully compiled and run on Windows System.The Output of the program is shown above .