A string literal is a sequence of one or more characters enclosed in double quotes:
cout<< "hello world"; // "hello world" is a char literal
By default, the compiler assumes a char-based literal. In order to create a string literal of wide characters, you should prefix the letter L to the string:
L"hello world" // now "hello world" is a wchar_t literal
Note that since the compiler is case sensitive, you must use a capital L.