Question

Explain recursive function. Write a program to find the GCD of a number by using recursive function. 

Answer 1

Recursive function :-
In C, a function can call itself. This process is known as recursion. And a function that calls itself is called as the recursive function. 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.

Program :-  

//Program to find GCD of a number by using recursive function.
#include <stdio.h>
#include <conio.h>
int gcd(int n1, int n2);
int main( )
{
       int n1, n2;
       printf("Enter two positive integers : \n");
       scanf("%d %d", &n1, &n2);
       g = gcd(n1,n2);
       printf("G.C.D of %d and %d is %d.", n1, n2, g);
       return 0;
}
int gcd(int n1, int n2)
{
      while (n1 != n2)
{
        if (n1 > n2)
            return gcd(n1 – n2, n2);
else
           return gcd(n1, n2 – n1);
}
return a;
}

Output :  

Enter two positive integers: 366 60 G.C.D of 366 and 60 is 6.