C++ Cookbook

13.1. Hardcoding a Unicode String

Problem

You have to hardcode a Unicode, i.e., wide-character, string in a source file.

Solution

Do this by hardcoding the string with a prefix of L and typing the character into your source editor as you would any other string, or use the hexadecimal number that represents the Unicode character you’re after. Example 13-1 shows how to do it both ways.

Example 13-1. Hardcoding a Unicode string

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

using namespace std;

int main() {

   // Create some strings with Unicode characters
   wstring ws1 = L"Infinity: \u221E";
   wstring ws2 = L"Euro: _";

   wchar_t w[] = L"Infinity: \u221E";

   wofstream out("tmp\\unicode.txt");
   out << ws2 << endl;
   wcout << ws2 << endl;
}

Discussion

Hardcoding a Unicode string is mostly a matter of deciding how you want to enter the string in your source editor. C++ provides a wide-character type, wchar_t, which can store Unicode strings. The exact implementation of wchar_t is implementation defined, but it is often UTF-32. The class wstring, defined in <string>, is a sequence of wchar_ts, just like the string class is a sequence of chars. (Strictly speaking, of course, wstring is a typedef for basic_string<wchar_t>).

The easiest way to enter Unicode characters is to use the L prefix to a string literal, as in Example 13-1:

wstring ws1 = L"Infinity: \u2210";  // Use the code itself
wstring ws2 = L"Euro: _";           // Or just type it in

Now, you can write these wide-character strings to a wide-character ...