C++如何在文件I/O中管理多个文件流

#include <fstream>
#include <iostream>
#include <string>

int main() {
    std::ifstream input1("data1.txt");
    std::ifstream input2("data2.txt");
    std::ofstream output1("result1.txt");
    std::ofstream output2("result2.txt");

    if (!input1.is_open() || !input2.is_open() ||
        !output1.is_open() || !output2.is_open()) {
        std::cerr << "无法打开一个或多个文件！\n";
        return 1;
    }

    std::string line;
    while (std::getline(input1, line)) {
        output1 << "文件1: " << line << '\n';
    }

    while (std::getline(input2, line)) {
        output2 << "文件2: " << line << '\n';
    }

    // 流对象在作用域结束时自动析构并关闭
    return 0;
}

#include <vector>
#include <fstream>
#include <string>
#include <memory>

std::vector<std::unique_ptr<std::ifstream>> fileReaders;

void openFiles(const std::vector<std::string>& filenames) {
    for (const auto& name : filenames) {
        auto file = std::make_unique<std::ifstream>(name);
        if (file->is_open()) {
            fileReaders.push_back(std::move(file));
        } else {
            std::cerr << "无法打开文件: " << name << '\n';
        }
    }
}

std::ofstream out("output.txt");
out.exceptions(std::ofstream::failbit | std::ofstream::badbit);
try {
    out << "数据写入\n";
} catch (const std::ios_base::failure& e) {
    std::cerr << "写入失败: " << e.what() << '\n';
}

std::ifstream temp("temp.dat");
// 读取操作...
temp.close(); // 显式关闭，释放资源