Thread: NEED help with returning the GCD

umm, i need help with this, i have no idea how to make it return the greatest common divisor, this code works without returning anything, but i need to make the code to RETURN it......i gotten everything down, just donno how to return the answer....

Code:

#include <stdio.h>
#include <stdlib.h>


int	GCD( int a,int b, int r);
int main()
{
	int	r,a,b;

      printf("Please enter two integers separated by a space: ");
      scanf("%d %d",&a,&b);

      printf("\nYou entered: %d %d ",a,b);
    
      if(a+b>0)
      {
        while (b)
        {
              r = a % b;
              a = b;
              b = r;
	    }
         r=GCD(a,b,r);
         printf("\n\n\nGCD: %d\n\n",r);
      }
      else
      {
         return 0;
      }

      system("PAUSE");
      return 0;
}

int GCD(int a,int b, int r)
{

   return ;

}