POJ 1269 Intersecting Lines 判断两直线关系

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define eps 1e-8
using namespace std;

struct Point
{
double x,y;
Point() {};
Point(double xx,double yy)
{
x=xx;
y=yy;
}
}ans;

int getCross(Point p1,Point p2,Point q1,Point q2)
{
double k1=(p1.y-p2.y)/(p1.x-p2.x);
double k2=(q1.y-q2.y)/(q1.x-q2.x);
double b1=p1.y-k1*p1.x;
double b2=q1.y-k2*q1.x;
if(p1.x==p2.x && q1.x==q2.x) return p1.x==q1.x? 1:-1;
if(p1.x==p2.x)
{
ans=Point(p1.x,k2*p1.x+b2);
return 0;
}
if(q1.x==q2.x)
{
ans=Point(q1.x,k1*q1.x+b1);
return 0;
}
if(fabs(k1-k2)<eps) return fabs(b1-b2)<eps? 1:-1;
ans.x=(b2-b1)/(k1-k2);
ans.y=k1*ans.x+b1;
return 0;
}

int main()
{
//    freopen("in.txt","r",stdin);
int t;
scanf("%d",&t);
Point pot[4];
puts("INTERSECTING LINES OUTPUT");
while(t--)
{
double x,y;
for(int i=0; i<4; i++)
{
scanf("%lf%lf",&x,&y);
pot[i]=Point(x,y);
}
int tmp=getCross(pot[0],pot[1],pot[2],pot[3]);
if(tmp==-1) puts("NONE");
else if(tmp==1) puts("LINE");
else printf("POINT %.2f %.2f\n",ans.x,ans.y);
}
puts("END OF OUTPUT");
return 0;
}