Convert to wstring

Converting a std::string to a std::wstring involves converting between narrow (char) and wide (wchar_t) characters. This is often necessary when dealing with different character encodings, such as ASCII and Unicode.

To convert a std::string to a std::wstring, you need to handle the conversion of each character. The simplest way to do this is to use the std::wstring constructor that takes a std::string as an argument. For example:

1#include <iostream>
2#include <string>
3
4int main() {
5  std::string NarrowString{"Hello, World!"};
6  std::wstring WideString{
7    NarrowString.begin(), NarrowString.end()
8  };  
9
10  std::wcout << WideString;
11}

1Hello, World!

For more control over the conversion, especially with different locales, you can use std::mbstowcs which stands for multi-byte string to wide-character string. For example:

1#include <iostream>
2#include <string>
3#include <cwchar>
4#include <vector>
5
6int main() {
7  std::string NarrowString{"Hello, World!"};
8  std::vector<wchar_t> WideString(
9    NarrowString.size() + 1
10  );
11
12  size_t convertedChars = 0;
13
14#ifdef _WIN32
15  mbstowcs_s(
16    &convertedChars, &WideString[0],
17    WideString.size(), NarrowString.c_str(),
18    NarrowString.size()
19  );
20#else
21  convertedChars = mbstowcs(
22    &WideString[0],
23    NarrowString.c_str(),
24    WideString.size()
25  );
26#endif
27
28  std::wcout << &WideString[0];
29}

1Hello, World!

• Locale: The conversion depends on the current C locale. You can set the locale using std::setlocale().
• Encoding: Ensure that the encoding of the std::string is compatible with the conversion process.

For more complex scenarios, such as converting between different character sets, consider using libraries like ICU (International Components for Unicode) or Boost.Locale.

1#include <boost/locale.hpp>
2#include <iostream>
3#include <string>
4
5int main() {
6  std::string NarrowString{"Hello, World!"};
7
8  std::wstring WideString =
9    boost::locale::conv::to_utf<wchar_t>(
10      NarrowString, "UTF-8"
11    );  
12
13  std::wcout << WideString;
14}

1Hello, World!

Converting between std::string and std::wstring allows you to handle different text encodings, making your applications more versatile in handling international text.