Thread: greatest common divisor is a prime number (pairs of numbers problem in C)

I have to build a program in C who reads a n integer number and n pairs of 2 integers numbers.The program should display those pairs of numbers I read whose greatest common divisor is a prime number.
My problem is that I get stuck at the code for reading the pairs of numbers and how to print them if they respect the condition. My code:

Code:

Code:

#include<stdio.h>
// find the gcd between 2 numbers
int gcd(int a,int b)
{
    if(a==0)
        return b;
    while(b!=0)
    {
        if(a>b)
        {
            a=a-b;
        }

        else
        {
            b=b-a;
        }
    }
    return a;
}
// check if a number is prime
int prime(int a)
{
   int i;
   if(a<2)
        return0;
   for(i=2;i<=a-1;i++)
   {
      if(a%i==0)
        return0;
   }
   return1;
}
int main()
{
    int n,i;
    int x,y,result;
    scanf("%d",&n);
    for(i=0;i<n;i++)
        {
            scanf("%d%d",&x,&y);
            printf("(%d,%d)",x,y);
            result=gcd(x,y);
        }
    for(i=0;i<n;i++)
    {
        if(prime(result)==1)
            printf("(%d,%d)",x,y);
    }
    return0;
}

My problem is in main function where I get stuck at this part of reading and displaying the pairs.For example if I enter n=3 and I read the following pairs: (12,20),(3,6) and (14,21) the program should display (3,6) and (14,21) because gcd of these pairs is a prime number.