View Code of Problem 67

#include<iostream>
#include<cmath>

using namespace std;

int main(){
	double x1;
	double x2;
	double x3;
	double x4;
	double y1;
	double y2;
	double y3;
	double y4;
	while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4){
		double k1;
		double k2;
		if(x1==x2){
			k1=10e7;
		} else {
			k1=(y1-y2)/(x1-x2);
		}
		if(x3==x4){
			k2=10e7;
		} else {
			k2=(y3-y4)/(x3-x4);
		}
		if(abs(k1-k2)<10e-7){
			cout<<"Yes"<<endl;
		} else {
			cout<<"No"<<endl;
		}
	}
	return 0;
}