用C++在VC6环境下写程序：设置两个小球，在窗口中进行运动 要求：当二者进行碰撞时，随机方向进行弹开，运动小球不能出窗口。

好的，以下是一份简单的C++代码，可以在VC6环境下实现你的需求。你可以在自己的项目中创建一个.cpp文件，命名为"ball.cpp"，并在VC6中编译运行。

#include <windows.h>
#include <iostream>
#include <time.h>
using namespace std;

#define ID_TIMER 1
#define BALL_RADIUS 50

// 小球结构体
struct Ball {
    int x, y;           // 小球圆心坐标
    int vx, vy;         // 小球速度
    int color;          // 小球颜色
};

// 定义全局变量
Ball ball1, ball2;
int ball1Color, ball2Color;
int ball1Speed, ball2Speed;
int ball1Direction, ball2Direction;
HWND hwnd;

// 函数声明
void InitBall(Ball& ball);
void MoveBall(Ball& ball);
void DrawBall(HDC hdc, Ball ball);
void CheckCollision();

// 主函数
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {

    // 初始化随机数生成器
    srand((unsigned)time(NULL));

    // 创建窗口
    HWND hwnd = CreateWindow("static", "", WS_VISIBLE | WS_BORDER | SS_CENTER, 100, 100, 800, 600, NULL, NULL, hInstance, NULL);

    // 初始化小球1
    InitBall(ball1);
    ball1Color = RGB(rand() % 255, rand() % 255, rand() % 255);
    ball1Speed = rand() % 10 + 1;
    ball1Direction = rand() % 360;

    // 初始化小球2
    InitBall(ball2);
    ball2Color = RGB(rand() % 255, rand() % 255, rand() % 255);
    ball2Speed = rand() % 10 + 1;
    ball2Direction = rand() % 360;

    // 设置定时器，每50毫秒移动小球
    SetTimer(hwnd, ID_TIMER, 50, NULL);

    // 消息循环
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return msg.wParam;
}

// 初始化小球
void InitBall(Ball& ball) {
    ball.x = rand() % (800 - BALL_RADIUS * 2) + BALL_RADIUS;
    ball.y = rand() % (600 - BALL_RADIUS * 2) + BALL_RADIUS;
    ball.vx = rand() % 10 + 1;
    ball.vy = rand() % 10 + 1;
}

// 移动小球
void MoveBall(Ball& ball) {
    // 根据速度和方向移动小球
    ball.x += ball.vx * cos(ball1Direction * 3.14 / 180);
    ball.y += ball.vy * sin(ball1Direction * 3.14 / 180);

    // 检测小球是否超出边界，如果是则弹回
    if (ball.x - BALL_RADIUS < 0 || ball.x + BALL_RADIUS > 800) {
        ball1Direction = 180 - ball1Direction;
        ball.x = ball.x - ball.vx * cos(ball1Direction * 3.14 / 180);
    }
    if (ball.y - BALL_RADIUS < 0 || ball.y + BALL_RADIUS > 600) {
        ball1Direction = 360 - ball1Direction;
        ball.y = ball.y - ball.vy * sin(ball1Direction * 3.14 / 180);
    }
}

// 绘制小球
void DrawBall(HDC hdc, Ball ball) {
    HBRUSH hBrush = CreateSolidBrush(ball.color);
    HBRUSH hOldBrush = (HBRUSH)SelectObject(hdc, hBrush);
    Ellipse(hdc, ball.x - BALL_RADIUS, ball.y - BALL_RADIUS, ball.x + BALL_RADIUS, ball.y + BALL_RADIUS);
    SelectObject(hdc, hOldBrush);
    DeleteObject(hBrush);
}

// 检测碰撞
void CheckCollision() {
    int dx = ball2.x - ball1.x;
    int dy = ball2.y - ball1.y;
    int distance = sqrt(dx * dx + dy * dy);
    if (distance < BALL_RADIUS * 2) {
        // 碰撞后随机改变方向
        ball1Direction = rand() % 360;
        ball2Direction = rand() % 360;
    }
}

// 窗口过程
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) {

    switch (message) {
    case WM_CREATE:
        break;
    case WM_PAINT:
        HDC hdc;
        PAINTSTRUCT ps;
        hdc = BeginPaint(hwnd, &ps);
        DrawBall(hdc, ball1);
        DrawBall(hdc, ball2);
        EndPaint(hwnd, &ps);
        break;
    case WM_TIMER:
        // 移动小球
        MoveBall(ball1);
        MoveBall(ball2);
        // 检测碰撞
        CheckCollision();
        // 重绘窗口
        InvalidateRect(hwnd, NULL, TRUE);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hwnd, message, wParam, lParam);
    }

    return 0;
}

注意，以上代码是一个简单的实现，你可以根据自己的实际需求进行修改和优化。