Question

If I want to use c++ to write a number (let’s say it is in hex format) to a binary file, for example,

#include <fstream>
#include <iostream>

using namespace std;

int main()
{
    int num = 0xabcd;
    ofstream outfile("tmp.bin", ios::out | ios::binary);
    outfile.seekp(0x8000, ios_base::beg);
    outfile.write(num, sizeof(num));
    return 0;
}

This program would not run since ostream& write() only takes char* chars[] as its first argument whereas I need to write a int type number num to the binary file “tmp.bin”.

The desired result is that when I view the “tmp.bin” in hex mode, I can see ab cd at address 0x8000. I am wondering if this is possible, and could anyone help me please? Thank you very much.

Answer 1

You can cast your int to a char*

outfile.write((char*)&num, sizeof(num));