C++ 读写二进制文件 read write binary file

[Shellbye]

对于我这种C++新人来说，用C++干个啥都很困难，似乎都需要记录。比如近日有这么一个需求，把一个二进制文件（old.wav）读取到内存里，返回给调用方，然后调用方在把它写入到一个新的二进制文件（new.wav）中。

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


std::vector<char> read_return() {
    std::ifstream file("old.wav", std::ios::binary | std::ios::ate);
    std::streamsize size = file.tellg();
    file.seekg(0, std::ios::beg);
    std::vector<char> buffer(size);
    if (file.read(buffer.data(), size)) {
        std::cout << "Read OK!" << std::endl;
        return buffer;
    } else {
        std::cout << "Read Failed!" << std::endl;
        return buffer;
    }
}

int main() {
    auto wav = read_return();
    
    std::ofstream stream("save.wav", std::ios::binary);
    stream.write((const char *) &wav[0], wav.size());
    stream.close();
    return 0;
}

参考：

1. https://stackoverflow.com/questions/18816126/c-read-the-whole-file-in-buffer
2. http://www.cplusplus.com/forum/beginner/76436/