View Code of Problem 67

#include<iostream>
using namespace std;


int main()
{
	double x1,y1,x2,y2,x3,y3,x4,y4;
	while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4)
	{
		double k1,k2,k3,k4;
		if(x1==x2)
			k1=0x3f3f3f3f;
		else
			k1=(y2-y1)/(x2-x1);
		if(x3==x4)
			k2=0x3f3f3f3f;
		else
			k2=(y4-y3)/(x4-x3);
		k3=(y4-y1)/(x4-x1);
		k4=(y3-y2)/(x3-x2);
		if(k1==k2 && k3!=k4) cout<<"No"<<endl;
		else cout<<"Yes"<<endl;
	}
}