# Strings library

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< cpp

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>`
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>; template<> class char_traits<char16_t>; template<> class char_traits<char32_t>; |  | (since C++20) (since C++11) (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).

### See also

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