C++中如何写入二进制文件？

#include <iostream>
#include <fstream>

int main() {
    // 打开文件以二进制写入模式
    std::ofstream file("example.bin", std::ios::binary);

    if (!file.is_open()) {
        std::cerr << "无法打开文件" << std::endl;
        return 1;
    }

    // 写入数据
    int number = 42;
    file.write(reinterpret_cast<const char*>(&number), sizeof(number));

    // 关闭文件
    file.close();

    std::cout << "数据已写入二进制文件" << std::endl;
    return 0;
}

#include <iostream>
#include <fstream>
#include <vector>
#include <stdexcept>

struct Person {
    char name[50];
    int age;
    double height;
};

int main() {
    std::vector<Person> people = {
        {"Alice", 30, 1.75},
        {"Bob", 25, 1.80}
    };

    try {
        std::ofstream file("people.bin", std::ios::binary);
        if (!file) {
            throw std::runtime_error("无法打开文件");
        }

        // 使用缓冲区优化写入
        std::vector<char> buffer;
        for (const auto& person : people) {
            buffer.insert(buffer.end(), person.name, person.name + 50);
            buffer.insert(buffer.end(), reinterpret_cast<const char*>(&person.age), reinterpret_cast<const char*>(&person.age) + sizeof(person.age));
            buffer.insert(buffer.end(), reinterpret_cast<const char*>(&person.height), reinterpret_cast<const char*>(&person.height) + sizeof(person.height));
        }

        file.write(buffer.data(), buffer.size());
        if (!file) {
            throw std::runtime_error("写入文件失败");
        }

        std::cout << "数据已写入二进制文件" << std::endl;
    } catch (const std::exception& e) {
        std::cerr << "错误: " << e.what() << std::endl;
        return 1;
    }

    return 0;
}