几何，求两整数点确定的线段上的整数点的个数

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
int gcd(int a,int b)
{
    return a%b==0?b:gcd(b,a%b);
}
int main()
{
    int x1,x2,y1,y2;
    while(cin>>x1>>y1>>x2>>y2)
    {
        int x=abs(x1-x2);
        int y=abs(y1-y2);
        int t=gcd(x,y);
        //cout<<t<<endl;
        cout<<y/(y/t)+1<<endl;
    }
    return 0;
}