1 #include <iostream>
2 #include <cstdio>
3 #include <cstring>
4 #include <cstdlib>
5 using namespace std;
6 struct point{
7 int x,y;
8 point(int x = 0,int y = 0){
9 this->x = x;
10 this->y = y;
11 }
12 };
13 struct line{
14 point st,en;
15 line(){}
16 };
17 class Intersect {
18 private:
19 line la,lb;
20 public:
21 void readData();
22 void process();
23 bool isCross();//
24 bool isSameLine();
25 };
26 void Intersect::readData(){
27 point p1,p2,p3,p4;
28 cin>>p1.x>>p1.y>>p2.x>>p2.y>>p3.x>>p3.y>>p4.x>>p4.y;
29 la.st = p1;la.en = p2;
30 lb.st = p3;lb.en = p4;
31 }
32 void Intersect::process(){
33 if(isCross()){
34 //求出交点
35 double A1 = la.st.y - la.en.y,B1 = la.en.x - la.st.x;
36 double C1 = la.st.x * la.en.y - la.st.y * la.en.x;//A1,B1,C1是方程系数
37 double A2 = lb.st.y - lb.en.y,B2 = lb.en.x - lb.st.x;
38 double C2 = lb.st.x * lb.en.y - lb.st.y * lb.en.x;
39 double x = (B1*C2 - B2*C1)/(A1*B2 - A2*B1);
40 double y = (C1*A2 - C2*A1)/(A1*B2 - A2*B1);//方程的解
41 printf("POINT %.2lf %.2lf
",x,y);
42 }
43 else{
44 if(isSameLine()==0){
45 cout<<"LINE"<<endl;
46 }
47 else
48 cout<<"NONE"<<endl;
49 }
50 }
51 bool Intersect::isCross(){//判断是否是相交的
52 if((la.en.x - la.st.x)*(lb.en.y - lb.st.y) ==
53 (la.en.y - la.st.y)*(lb.en.x - lb.st.x)){
54 return false;
55 }
56 else
57 return true;
58 }
59 bool Intersect::isSameLine(){//用向量叉积判断点是否在线上
60 return (lb.st.x-lb.en.x)*(la.st.y-lb.en.y)-(la.st.x-lb.en.x)*(lb.st.y-lb.en.y);
61 }
62 int main()
63 {
64 int cases;
65 Intersect intersect;
66 #ifndef ONLINE_JUDGE
67 freopen("D://acm.txt","r",stdin);
68 #endif // ONLINE_JUDGE
69 while(cin>>cases){
70 cout<<"INTERSECTING LINES OUTPUT"<<endl;
71 while(cases--){
72 intersect.readData();
73 intersect.process();
74 }
75 cout<<"END OF OUTPUT"<<endl;
76 }
77 return 0;
78 }
