用C++写两个小球碰撞

好的，下面是一个简单的用 C++ 编写的小球碰撞模拟程序，希望对您有所帮助。

#include <iostream>
#include <cmath>

using namespace std;

const double PI = 3.141592653589793;

class Ball {
public:
    Ball(double x, double y, double r, double vx, double vy, double m)
        : x_(x), y_(y), r_(r), vx_(vx), vy_(vy), m_(m) {}

    double GetX() const { return x_; }
    double GetY() const { return y_; }
    double GetRadius() const { return r_; }
    double GetVx() const { return vx_; }
    double GetVy() const { return vy_; }
    double GetMass() const { return m_; }

    void SetX(double x) { x_ = x; }
    void SetY(double y) { y_ = y; }
    void SetVx(double vx) { vx_ = vx; }
    void SetVy(double vy) { vy_ = vy; }

    void Move(double dt) {
        x_ += vx_ * dt;
        y_ += vy_ * dt;
    }

    friend bool IsCollided(const Ball& b1, const Ball& b2) {
        double dx = b1.x_ - b2.x_;
        double dy = b1.y_ - b2.y_;
        double d = sqrt(dx * dx + dy * dy);
        return d <= b1.r_ + b2.r_;
    }

    friend void Collide(Ball& b1, Ball& b2) {
        double dx = b1.x_ - b2.x_;
        double dy = b1.y_ - b2.y_;
        double d = sqrt(dx * dx + dy * dy);
        if (d < 1e-6) return;  // 重叠了就不碰撞了
        double nx = dx / d;
        double ny = dy / d;
        double tx = -ny;
        double ty = nx;
        double v1n = b1.vx_ * nx + b1.vy_ * ny;
        double v1t = b1.vx_ * tx + b1.vy_ * ty;
        double v2n = b2.vx_ * nx + b2.vy_ * ny;
        double v2t = b2.vx_ * tx + b2.vy_ * ty;
        double v1n_ = (v1n * (b1.m_ - b2.m_) + 2 * b2.m_ * v2n) / (b1.m_ + b2.m_);
        double v2n_ = (v2n * (b2.m_ - b1.m_) + 2 * b1.m_ * v1n) / (b1.m_ + b2.m_);
        b1.vx_ = v1n_ * nx + v1t * tx;
        b1.vy_ = v1n_ * ny + v1t * ty;
        b2.vx_ = v2n_ * nx + v2t * tx;
        b2.vy_ = v2n_ * ny + v2t * ty;
    }

private:
    double x_;  // x 坐标
    double y_;  // y 坐标
    double r_;  // 半径
    double vx_;  // x 方向速度
    double vy_;  // y 方向速度
    double m_;  // 质量
};

int main() {
    double x1 = 0, y1 = 0, r1 = 1, vx1 = 1, vy1 = 0, m1 = 1;
    double x2 = 3, y2 = 0, r2 = 1, vx2 = -1, vy2 = 0, m2 = 1;
    Ball b1(x1, y1, r1, vx1, vy1, m1);
    Ball b2(x2, y2, r2, vx2, vy2, m2);
    double dt = 0.01;
    int steps = 1000;
    for (int i = 0; i < steps; ++i) {
        if (IsCollided(b1, b2)) {
            Collide(b1, b2);
        }
        b1.Move(dt);
        b2.Move(dt);
        cout << "step " << i << ": (" << b1.GetX() << ", " << b1.GetY() << "), (" << b2.GetX() << ", " << b2.GetY() << ")" << endl;
    }
    return 0;
}

以上代码中，我们定义了一个 `Ball` 类，表示一个小球，其中包含了小球的位置、半径、速度和质量等信息。我们还定义了两个函数 `IsCollided` 和 `Collide`，分别用于判断两个小球是否碰撞，并进行碰撞处理。在主函数中，我们创建了两个小球，并模拟它们的运动过程，输出每一步后两个小球的位置信息。