C ++：如何直接写入文件（无ASCII）？

Question

I need to write to a file directly (file format/extension doesn't matter). What I want to be able to do is, eg write A to it, and if I opened the file with a hex editor, it would display A, aka the value 10 in decimal.

Answer 1

#include <iostream>
int main()
{
    std::ofstream fout("myfile.ext", std::ios::binary);
    std::ofstream::char_type byte = 10; //or = 0xA
    fout.put(byte);
}

Answer 2

Well, if you write 'A' to the file, I'd expect the hex editor to show 41.

But let's say we have an int x = 0xa; , then the way to write that to a file is:

int x = 0xa;
ofstream out("myfile.txt", ios::out|ios::binary);

out.write((char *)&x, sizeof(x)); 

out.close();

Note that this code isn't highly portable, since size of int and the order of bytes within an integer can change from architecture to architecture.