How to convert Byte Array to Hexadecimal String in C++?

Question

I am looking for a fastest way to convert a byte array of arbitrary length to a hexadecimal string. This question has been fully answered here at StackOverflow for C#. Some

Answer 1

You can use the C++ Standard Library and or you can use boost::lexical_cast

#include 
#include 
#include 
#include 
#include 
#include 
#include 

using namespace std;

// use this macro for c++11 feature
#define USE_CPP11

int main(int argc, char* argv[])
{
    array hexArr = {0x01, 0xff, 0x55};
    const char separator = ' ';             // separator between two numbers
    ostringstream os;
    os << hex << setfill('0');  // set the stream to hex with 0 fill

#ifdef USE_CPP11
    std::for_each(std::begin(hexArr), std::end(hexArr), [&os, &separator] (int i)
    {
        os << setw(2) << i << separator;
    });
#else       // c++03
    typedef array::const_iterator const_iterator;
    for (const_iterator it = hexArr.begin(); it != hexArr.end(); ++it)
    {
        os << setw(2) << int(*it) << separator;
    }
#endif
    os << dec << setfill(' ');          // reset the stream to "original"

    // print the string
    cout << "the string array is: " << os.str() << endl;

    return EXIT_SUCCESS;
}