Question

I need to read 16 bits from the binary file as std::string or char *. For example, a binary file contains 89 ab cd ef, and I want to be able to extract them as std::strings or char *. I have tried the following code:

ifstream *p = new ifstream();
char *buffer;  
p->seekg(address, ios::beg);  
buffer = new char[16];  
memset(buffer, 0, 16);  
p->read(buffer, 16);  

When I try to std::cout the buffer, nothing appeared. How can I read these characters in the binary file?

EDIT: I was looking for the buffer to be a int type such as “0x89abcdef”. Is it possible to achieve?

Answer 1

Something like:

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

int main()
{
    if (ifstream input("filename"))
    {
        std::string s(2 /*bytes*/, '\0' /*initial content - irrelevant*/);
        if (input.read(&s[0], 2 /*bytes*/))
            std::cout << "SUCCESS: [0] " << std::hex << (int)s[0] << " [1] " << (int)s[1] << '\n';
        else
            std::cerr << "Couldn't read from file\n";
    }
    else
        std::cerr << "Couldn't open file\n";
}