判断点是否在A(x1,y1),B(x2,y2)连线的直线上

#include <iostream>using namespace std;typedef struct //直线方程{double a;double b;double c;}Tline;typedef struct //点坐标{double x;double y;}Tpoint;//根据两点坐标求出直线方程 A(x1,y1) B(x2,y2)//方程为(y2-y1)x+(x1-x2)y+2x1*y1-x1*y2+x2*y1;Tline lineFormSegment(Tpoint p1,Tpoint p2){Tline temp;temp.a = p2.y-p1.y; temp.b = p1.x-p2.x;temp.c = 2*p1.x*p1.y-p1.x*p2.y*p2.x*p1.y;return temp;}bool IsOnline(Tpoint p,Tline line){return line.a*p.x+line.b*p.y+line.c==0;}int main(){Tpoint p1;p1.x=0;p1.y=0;Tpoint p2;p2.x=0;p2.y=1;Tpoint p3;p3.x=2;p3.y=2;Tline line =lineFormSegment(p1,p3);if(IsOnline(p2,line))printf("online/n");return 0;}