直线相交 POJ 1269

 // 直线相交 POJ 1269

 // #include <bits/stdc++.h>
 #include <iostream>
 #include <cstdio>
 #include <cstdlib>
 #include <algorithm>
 #include <math.h>
 using namespace std;
 #define LL long long
 typedef pair<int,int> pii;
 const double inf = 123456789012345.0;
 const LL MOD =100000000LL;
 const int N =1e4+;
 #define clc(a,b) memset(a,b,sizeof(a))
 const double eps = 1e-;
 void fre() {freopen("in.txt","r",stdin);}
 void freout() {freopen("out.txt","w",stdout);}
 inline int read() {int x=,f=;char ch=getchar();while(ch>''||ch<'') {if(ch=='-') f=-; ch=getchar();}while(ch>=''&&ch<='') {x=x*+ch-'';ch=getchar();}return x*f;}

 int sgn(double x){
     if(fabs(x) < eps)return ;
     if(x < )return -;
     else return ;
 }
 struct Point{
     double x,y;
     Point(){}
     Point(double _x,double _y){
         x = _x;y = _y;
     }
     Point operator -(const Point &b)const{
         return Point(x - b.x,y - b.y);
     }
     double operator ^(const Point &b)const{
         return x*b.y - y*b.x;
     }
     double operator *(const Point &b)const{
         return x*b.x + y*b.y;
     }
 };

 struct Line{
     Point s,e;
     Line(){}
     Line(Point _s,Point _e){
         s=_s;e=_e;
     }
     pair<int,Point> operator & (const Line &b) const{
         Point res=s;
         if(sgn((s-e)^(b.s-b.e))==){
             if(sgn((s-b.e)^(b.s-b.e))==)
                 return make_pair(,res);
             else  return make_pair(,res);
         }
         double t=((s-b.s)^(b.s-b.e))/((s-e)^(b.s-b.e));
         res.x+=(e.x-s.x)*t;
         res.y+=(e.y-s.y)*t;
         return make_pair(,res);
     }
 };

 int main(){
     int T;
     scanf("%d",&T);
     double x1,x2,x3,x4,y1,y2,y3,y4;
     printf("INTERSECTING LINES OUTPUT\n");
     while(T--){
         scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4);
         Line line1 = Line(Point(x1,y1),Point(x2,y2));
         Line line2 = Line(Point(x3,y3),Point(x4,y4));
         pair<int,Point> ans=line1 & line2;
         if(ans.first==) printf("LINE\n");
         else if(ans.first==) printf("NONE\n");
         else printf("POINT %.2f %.2f\n",ans.second.x,ans.second.y);
     }
     printf("END OF OUTPUT\n");
     return ;
 }