如何获取txt文件中的随机字符串(c++ ifstream)？

#include <iostream>
#include <fstream>
#include <string>
#include <cstdlib> // for rand() and srand()
#include <ctime>   // for time()

std::string getRandomStringFromFile(const std::string& filename) {
    std::ifstream file(filename);
    if (!file.is_open()) {
        throw std::runtime_error("Could not open file");
    }

    // 获取文件大小
    file.seekg(0, std::ios::end);
    std::streampos fileSize = file.tellg();
    file.seekg(0, std::ios::beg);

    // 生成随机位置
    std::srand(static_cast<unsigned int>(std::time(nullptr))); // 使用当前时间作为随机数种子
    std::streampos randomPos = std::rand() % fileSize;

    // 定位到随机位置并读取字符串
    file.seekg(randomPos);
    std::string randomString;
    if (randomPos + 1 < fileSize) {
        randomString = file.getline();
    } else {
        // 如果随机位置在文件末尾，读取剩余的所有字符
        randomString.assign((std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>());
    }

    file.close();
    return randomString;
}

int main() {
    try {
        std::string filename = "example.txt";
        std::string randomString = getRandomStringFromFile(filename);
        std::cout << "Random string from file: " << randomString << std::endl;
    } catch (const std::exception& e) {
        std::cerr << "Error: " << e.what() << std::endl;
    }
    return 0;
}