1.C++实现：计算点 C 到一条线 AB 的距离_c++垂足计算

#include <iostream>
#include <algorithm>

using namespace std;
double calDistance(double x1, double x2, double y1, double y2){
    double s1 = pow((x1 - x2),2) + pow((y1 - y2), 2);
    return sqrt(s1);
}
void test(){
    double C_x(3), C_y(0), A_x(0), A_y(0), B_x(2), B_y(2);
    double distance_a = calDistance(C_x, A_x, C_y, A_y);
    double distance_b = calDistance(A_x, B_x, A_y, B_y);
    double distance_c = calDistance(C_x, B_x, C_y, B_y);
    double s = (distance_a + distance_b + distance_c)/2;

    double area_tmp = s * (s - distance_a) * (s - distance_b) * (s - distance_c);
    area_tmp = area_tmp < 0 ? -area_tmp : area_tmp;

    double triangle_area = sqrt(area_tmp);

    double x_error = 2 * triangle_area / distance_b;
    cout << x_error << endl;
}
int main(){
	test();
	return 0;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27