为游戏石头剪刀布 编写 C++ 程序

为"石头剪刀布"游戏编写C++程序，可以参考上面提供的代码片段。这个程序会提示用户输入他们的选择（R代表石头，P代表纸，S代表剪刀），然后生成计算机随机选择，再根据游戏规则判断胜负。程序会循环进行直到用户选择退出。

下面是一个简化版的代码示例：

#include <iostream>
#include <ctime>
#include <cstdlib>

enum Choices { ROCK, PAPER, SCISSORS };

int getComputerChoice() {
    srand(time(0));
    return rand() % 3 + 1; // 加1是因为数组索引从1开始
}

void getUserInput() {
    std::cout << "Enter your choice (rock, paper, scissors): ";
    char userChoice;
    std::cin >> userChoice;
    if (userChoice != 'r' && userChoice != 'p' && userChoice != 's') {
        std::cout << "Invalid input! Try again.\n";
        getUserInput(); // 如果输入无效，再次请求
    } else {
        userChoice = userChoice == 'r' ? ROCK : (userChoice == 'p' ? PAPER : SCISSORS);
    }
}

void determineWinner(const Choices& userChoice, const Choices& computerChoice) {
    if (userChoice == computerChoice) {
        std::cout << "It's a tie!\n";
    } else if ((userChoice == ROCK && computerChoice == SCISSORS) ||
               (userChoice == PAPER && computerChoice == ROCK) ||
               (userChoice == SCISSORS && computerChoice == PAPER)) {
        std::cout << "You win!\n";
    } else {
        std::cout << "Computer wins!\n";
    }
}

int main() {
    bool playAgain = true;
    while (playAgain) {
        Choices userChoice, computerChoice;
        getUserInput();
        computerChoice = getComputerChoice();
        determineWinner(userChoice, computerChoice);

        std::cout << "Do you want to play again? (y/n): ";
        std::cin >> playAgain;
    }
    return 0;
}