18.15. Write a function that gets two positive returns GCD (greatest common divisor).

#include<stdio.h>
#include<conio.h>
int GCD(int a, int b)
{
int c=0;

while(a%b!=0)

{

c=a%b;

a=b;

b=c;

}

return b;

}

void main ()
{
int a,b;
clrscr();
printf("Enter any positive integer: ");
scanf ("%d", &a);

printf("Enter any positive integer: ");
scanf ("%d", &b);
printf("GCD of %d=%d", GCD(a,b)) ;
getch ();
}