Strings library

 

C++

Compiler support

Freestanding and hosted

Language

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

basic_string_view (C++17)

char_traits

 

The C++ strings library includes support for three general types of strings:

• std::basic_string - a templated class designed to manipulate strings of any character type.
• std::basic_string_view (C++17) - a lightweight non-owning read-only view into a subsequence of a string.
• Null-terminated strings - arrays of characters terminated by a special null character.

std::basic_string

The templated class std::basic_string generalizes how sequences of characters are manipulated and stored. String creation, manipulation, and destruction are all handled by a convenient set of class methods and related functions.

Several specializations of std::basic_string are provided for commonly-used types:

Defined in header <string>
Type	Definition
std::string	std::basic_string<char>
std::wstring	std::basic_string<wchar_t>
std::u8string (since C++20)	std::basic_string<char8_t>
std::u16string (since C++11)	std::basic_string<char16_t>
std::u32string (since C++11)	std::basic_string<char32_t>

std::basic_string_view The templated class std::basic_string_view provides a lightweight object that offers read-only access to a string or a part of a string using an interface similar to the interface of std::basic_string. Several specializations of std::basic_string_view are provided for commonly-used types: Defined in header <string_view> Type Definition std::string_view (since C++17) std::basic_string_view<char> std::wstring_view (since C++17) std::basic_string_view<wchar_t> std::u8string_view (since C++20) std::basic_string_view<char8_t> std::u16string_view (since C++17) std::basic_string_view<char16_t> std::u32string_view (since C++17) std::basic_string_view<char32_t>

(since C++17)

Null-terminated strings

Null-terminated strings are arrays of characters that are terminated by a special null character. C++ provides functions to create, inspect, and modify null-terminated strings.

There are three types of null-terminated strings:

• null-terminated byte strings
• null-terminated multibyte strings
• null-terminated wide strings

Additional support

std::char_traits

The string library also provides class template std::char_traits that defines types and functions for std::basic_string and std::basic_string_view (since C++17). The following specializations are defined:

Defined in header <string>
template<> class char_traits<char>;
template<> class char_traits<wchar_t>;
template<> class char_traits<char8_t>;		(since C++20)
template<> class char_traits<char16_t>;		(since C++11)
template<> class char_traits<char32_t>;		(since C++11)

Conversions and classification

The localizations library provides support for string conversions (e.g. std::wstring_convert or std::toupper) as well as functions that classify characters (e.g. std::isspace or std::isdigit).