中望cad只指定两个点画圆弧的命令C++

中望CAD只指定两个点画圆弧的命令是通过Pline命令的Arc选项实现的，其C++代码如下：

#include <iostream>
#include <cmath>

using namespace std;

// 定义圆弧结构体
struct Arc {
    double start_x;
    double start_y;
    double end_x;
    double end_y;
    double center_x;
    double center_y;
    double radius;
    double start_angle;
    double end_angle;
};

// 计算圆心坐标和半径
Arc calculateArc(double start_x, double start_y, double end_x, double end_y) {
    Arc arc;
    arc.start_x = start_x;
    arc.start_y = start_y;
    arc.end_x = end_x;
    arc.end_y = end_y;
    arc.center_x = (start_x + end_x) / 2;
    arc.center_y = (start_y + end_y) / 2;
    arc.radius = sqrt(pow(end_x - start_x, 2) + pow(end_y - start_y, 2)) / 2;
    arc.start_angle = atan2(start_y - arc.center_y, start_x - arc.center_x);
    arc.end_angle = atan2(end_y - arc.center_y, end_x - arc.center_x);

    return arc;
}

int main() {
    // 模拟用户输入的起点和终点
    double start_x = 0;
    double start_y = 0;
    double end_x = 5;
    double end_y = 5;

    // 计算圆心坐标和半径
    Arc arc = calculateArc(start_x, start_y, end_x, end_y);

    // 输出圆心坐标和半径
    cout << "Center point: (" << arc.center_x << ", " << arc.center_y << ")" << endl;
    cout << "Radius: " << arc.radius << endl;

    return 0;
}

在calculateArc函数中，我们首先计算出圆心坐标和半径，其中圆心坐标为起点和终点的中点，半径为起点和终点之间的距离的一半。接着，我们根据圆心坐标和起点、终点的坐标，计算出圆弧的起始角度和终止角度。在主函数中，我们模拟了用户输入的起点和终点，然后调用calculateArc函数来计算圆心坐标和半径，并输出结果。注意，这里只是一个示例，实际应用中还需要考虑更多的因素。