std::wstring to std::string

cpp-stdwstring-to-stdstring.cpp

#include <iostream>
#include <string>

#include <cassert>
#include <iostream>
#include <string>

#include <locale>
#include <codecvt>

std::string AsStdStringByConverter(std::wstring ws)
{
    using convert_type = std::codecvt_utf8<wchar_t>;
    std::wstring_convert<convert_type, wchar_t> converter;
    // converter (.to_bytes: wstr->str, .from_bytes: str->wstr)
    return converter.to_bytes(ws);    
}

//std::string AsStdStringByConverter(std::wstring& wstring)
//{
//    using convert_type = std::codecvt<wchar_t, char, std::mbstate_t>;
//    std::wstring_convert<convert_type, wchar_t> converter;
//    return converter.to_bytes(wstring);
//}

std::string AsStdStringByRaw(std::wstring ws)
{
    return std::string((const char*)&ws[0], sizeof(wchar_t) / sizeof(wchar_t) * ws.size());
}

std::string AsStdStringConstructed(std::wstring ws)
{
    return std::string(ws.begin(), ws.end());
}

int main()
{
    std::wstring ws0 = L"Hællo";
    // UTF-8
    std::string utf8_s0 = AsStdStringByConverter(ws0);
    std::string utf8_s1 = AsStdStringByRaw(ws0);
    std::string utf8_s2 = AsStdStringConstructed(ws0);
    
    std::cout << "utf8_s0: " << utf8_s0 << ", size: " << utf8_s0.size() << std::endl;
    std::cout << "utf8_s1: " << utf8_s1 << ", size: " << utf8_s1.size() << std::endl;
    std::cout << "utf8_s2: " << utf8_s2 << ", size: " << utf8_s2.size() << std::endl;
    
    std::wstring ws1 = L"\x0040\x03A6\x0298";
    // UTF-16
    std::string utf16_s0 = AsStdStringByConverter(ws1);
    std::string utf16_s1 = AsStdStringByRaw(ws1);
    std::string utf16_s2 = AsStdStringConstructed(ws1);
    
    std::cout << "utf16_s0: " << utf16_s0 << ", size: " << utf16_s0.size() << std::endl;
    std::cout << "utf16_s1: " << utf16_s1 << ", size: " << utf16_s1.size() << std::endl;
    std::cout << "utf16_s2: " << utf16_s2 << ", size: " << utf16_s2.size() << std::endl;

    return 0;
}