View Code of Problem 67

#include <iostream>
using namespace std;
int main(){
	double x1,x2,x3,x4,y1,y2,y3,y4;
	while(cin>>x1>>y1>>x2>>y2){
		cin>>x3>>y3>>x4>>y4;
		double k1=0,k2=0;
		
		if(x2!=x1&&x4!=x3){				
			k1=1.0*(y2-y1)/(x2-x1);
			k2=1.0*(y4-y3)/(x4-x3);
			if(k1!=k2){
				cout<<"Yes"<<endl;
			}else{
				if(y1-k1*x1!=y3-k2*x3)	cout<<"No"<<endl;
				else
				cout<<"Yes"<<endl;
			}
		}
		else if((x2==x1)&&(x4==x3)){				
				if(x1==x3)
					cout<<"Yes"<<endl;
				else
					 cout<<"No"<<endl;
				}
		else{
				cout<<"Yes"<<endl;
			}
			
	}
}