. There are four different points on a plane: A(x1, y1), B(x2, y2), C(x3, y3) and D(x4, y4). Write a C++ program to check whether two straight lines AB and CD are orthogonal or not

#include <iostream>
using namespace std;
int main(void)
{
    double x[4],y[4];
    while(cin >> x[0] >> y[0]){
        for(int i=1; i<4; i++){
            cin >> x[i] >> y[i];
        }
        if( (x[1]-x[0])*(x[3]-x[2])+(y[3]-y[2])*(y[1]-y[0]) == 0 )
        {
            cout << "Yes, AB and CD are orthogonal." << endl;
        }
        else
        {
            cout << "Yes, AB and CD are not orthogonal." << endl;
        }
    }
    return 0;
}