Using the string class as a container

C++ strings are based on the basic_string template class. This class is a container, so it uses iterator access and methods to obtain information, and has template parameters that contain information about the character type it holds. There are different typedef for specific character types:

    typedef basic_string<char,
       char_traits<char>, allocator<char> > string; 
    typedef basic_string<wchar_t,
       char_traits<wchar_t>, allocator<wchar_t> > wstring; 
    typedef basic_string<char16_t,
       char_traits<char16_t>, allocator<char16_t> > u16string; 
    typedef basic_string<char32_t,
       char_traits<char32_t>, allocator<char32_t> > u32string;

The string class is based on char, wstring is based on wchar_t wide characters, and the 16string and u32string classes are based upon 16-bit and 32-bit characters, respectively. For the rest of the chapter, we will concentrate...