在C ++中找到三角形的圆心的程序
在本教程中，我们将讨论一个寻找三角形外接点的程序。
为此，我们将提供三个非共线点。我们的任务是找到由这些点形成的三角形的外心。
示例
#include <iostream>
#include <cfloat>
using namespace std;
//存储X和Y值
#define pdd pair<double, double>
void lineFromPoints(pdd P, pdd Q, double &a, double &b, double &c){
a = Q.second - P.second;
b = P.first - Q.first;
c = a*(P.first)+ b*(P.second);
}
void perpendicularBisectorFromLine(pdd P, pdd Q, double &a, double &b, double &c){
pdd mid_point = make_pair((P.first + Q.first)/2, (P.second + Q.second)/2);
c = -b*(mid_point.first) + a*(mid_point.second);
double temp = a;
a = -b;
b = temp;
}
pdd lineLineIntersection(double a1, double b1, double c1, double a2, double b2, double c2){
double determinant = a1*b2 - a2*b1;
if (determinant == 0){
return make_pair(FLT_MAX, FLT_MAX);
} else {
double x = (b2*c1 - b1*c2)/determinant;
double y = (a1*c2 - a2*c1)/determinant;
return make_pair(x, y);
}
}
void findCircumCenter(pdd P, pdd Q, pdd R){
double a, b, c;
lineFromPoints(P, Q, a, b, c);
double e, f, g;
lineFromPoints(Q, R, e, f, g);
perpendicularBisectorFromLine(P, Q, a, b, c);
perpendicularBisectorFromLine(Q, R, e, f, g);
pdd circumcenter = lineLineIntersection(a, b, c, e, f, g);
if (circumcenter.first == FLT_MAX && circumcenter.second == FLT_MAX){
cout << "两条垂直平分线 "
"找到了平行线" << endl;
cout << "因此，给定的点不会形成 "
"三角形且共线" << endl;
} else {
cout << "三角形PQR的外心为: ";
cout << "(" << circumcenter.first << ", "
<< circumcenter.second << ")" << endl;
}
}
int main(){
pdd P = make_pair(6, 0);
pdd Q = make_pair(0, 0);
pdd R = make_pair(0, 8);
findCircumCenter(P, Q, R);
return 0;
}输出结果
三角形PQR的外心为: (3, 4)