怎样用C++制作简易抽奖程序 随机算法和名单读取方法

#include <iostream>
#include <vector>
#include <string>
#include <fstream>
#include <random>
#include <algorithm>

// 从文件中读取名单
std::vector<std::string> readNamesFromFile(const std::string& filename) {
    std::vector<std::string> names;
    std::ifstream file(filename);
    std::string name;
    if (file.is_open()) {
        while (std::getline(file, name)) {
            names.push_back(name);
        }
        file.close();
    } else {
        std::cerr << "Unable to open file: " << filename << std::endl;
    }
    return names;
}

// 抽奖函数
std::string drawWinner(std::vector<std::string>& names) {
    if (names.empty()) {
        return "No participants available.";
    }

    std::random_device rd;
    std::mt19937 gen(rd());
    std::uniform_int_distribution<> distrib(0, names.size() - 1);

    int randomIndex = distrib(gen);
    std::string winner = names[randomIndex];
    names.erase(names.begin() + randomIndex); // 防止重复中奖
    return winner;
}

int main() {
    std::string filename = "names.txt"; // 参与者名单文件
    std::vector<std::string> participants = readNamesFromFile(filename);

    if (participants.empty()) {
        std::cout << "No participants found. Please check the file." << std::endl;
        return 1;
    }

    std::cout << "Press Enter to draw a winner..." << std::endl;
    std::cin.get(); // 等待用户按下Enter键

    std::string winner = drawWinner(participants);
    std::cout << "The winner is: " << winner << std::endl;

    return 0;
}