为什么会有语法错误aaaaa

#include<iostream>
#include<math.h>

using namespace std;

int coprime(int x,int y)
{
	if(y == 0) 
	{
	    return x;
	}
	else 
	{
	    return ( coprime(y , x % y) );
	}
}

int num , x1 , x2 , y1 , y2;

int main()
{
    cin>>num;
    for(int i = 0 ; i < num ; i++)
    {
        cin>>x1>>x2>>y1>>y2;
        if( coprime(abs(x1 - y1) , abs(x2 - y2)) == 1)
        {
            cout<<"no"<<endl;
        }
        else
        {
            cout<<"yes"<<endl;
        }
    }
}