class template

std::basic_string

template < class charT,
           class traits = char_traits<charT>,    // basic_string::traits_type
           class Alloc = allocator<charT>        // basic_string::allocator_type
           > class basic_string;

Generic string class

The basic_string is the generalization of class string for any character type (see string for a description).

Template parameters

charT: Character type.
The string is formed by a sequence of characters of this type.
This shall be a non-array POD type.
traits: Character traits class that defines essential properties of the characters used by basic_string objects (see char_traits).
traits::char_type shall be the same as charT.
Aliased as member type basic_string::traits_type.
Alloc: Type of the allocator object used to define the storage allocation model. By default, the allocator class template is used, which defines the simplest memory allocation model and is value-independent.
Aliased as member type basic_string::allocator_type.

Note: Because the first template parameter is not aliased as any member type, charT is used throughout this reference to refer to this type.

Template instantiations

string: String class (class )

wstring: Wide string (class )

u16string: String of 16-bit characters (class )

u32string: String of 32-bit characters (class )

Member types

member type	definition	notes
`traits_type`	The second template parameter (`traits`)	defaults to: `char_traits<charT>`
`allocator_type`	The third template parameter (`Alloc`)	defaults to: `allocator<charT>`
`value_type`	`traits_type::char_type`	shall be the same as `charT`
`reference`	`allocator_type::reference`	for the default allocator: `charT&`
`const_reference`	`allocator_type::const_reference`	for the default allocator: `const charT&`
`pointer`	`allocator_type::pointer`	for the default allocator: `charT*`
`const_pointer`	`allocator_type::const_pointer`	for the default allocator: `const charT*`
`iterator`	a random access iterator to `charT`	convertible to `const_iterator`
`const_iterator`	a random access iterator to `const charT`
`reverse_iterator`	`reverse_iterator<iterator>`
`const_reverse_iterator`	`reverse_iterator<const_iterator>`
`difference_type`	`allocator_type::difference_type`	usually the same as ptrdiff_t
`size_type`	`allocator_type::difference_type`	usually the same as size_t

member type	definition	notes
`traits_type`	The second template parameter (`traits`)	defaults to: `char_traits<charT>`
`allocator_type`	The third template parameter (`Alloc`)	defaults to: `allocator<charT>`
`value_type`	`traits_type::char_type`	shall be the same as `charT`
`reference`	`value_type&`
`const_reference`	`const value_type&`
`pointer`	`allocator_traits<allocator_type>::pointer`	for the default allocator: `charT*`
`const_pointer`	`allocator_traits<allocator_type>::const_pointer`	for the default allocator: `const charT*`
`iterator`	a random access iterator to `charT`	convertible to `const_iterator`
`const_iterator`	a random access iterator to `const charT`
`reverse_iterator`	`reverse_iterator<iterator>`
`const_reverse_iterator`	`reverse_iterator<const_iterator>`
`difference_type`	`allocator_traits<allocator_type>::difference_type`	usually the same as ptrdiff_t
`size_type`	`allocator_traits<allocator_type>::difference_type`	usually the same as size_t

Member functions

(constructor): Construct basic_string object (public member function )

(destructor): String destructor (public member function )

operator=: String assignment (public member function )

Iterators:

begin: Return iterator to beginning (public member function )

end: Return iterator to end (public member function )

rbegin: Return reverse iterator to reverse beginning (public member function )

rend: Return reverse iterator to reverse end (public member function )

cbegin: Return const_iterator to beginning (public member function )

cend: Return const_iterator to end (public member function )

crbegin: Return const_reverse_iterator to reverse beginning (public member function )

crend: Return const_reverse_iterator to reverse end (public member function )

Capacity:

size: Return size (public member function )

length: Return length of string (public member function )

max_size: Return maximum size (public member function )

resize: Resize string (public member function )

capacity: Return size of allocated storage (public member function )

reserve: Request a change in capacity (public member function )

clear: Clear string (public member function )

empty: Test whether string is empty (public member function )

shrink_to_fit: Shrink to fit (public member function )

Element access:

operator[]: Get character of string (public member function )

at: Get character of string (public member function )

back: Access last character (public member function )

front: Access first character (public member function )

Modifiers:

operator+=: Append to string (public member function )

append: Append to string (public member function )

push_back: Append character to string (public member function )

assign: Assign content to string (public member function )

insert: Insert into string (public member function )

erase: Erase characters from string (public member function )

replace: Replace portion of string (public member function )

swap: Swap string values (public member function )

pop_back: Delete last character (public member function )

String operations:

c_str: Get C-string equivalent

data: Get string data (public member function )

get_allocator: Get allocator (public member function )

copy: Copy sequence of characters from string (public member function )

find: Find first occurrence in string (public member function )

rfind: Find last occurrence in string (public member function )

find_first_of: Find character in string (public member function )

find_last_of: Find character in string from the end (public member function )

find_first_not_of: Find non-matching character in string (public member function )

find_last_not_of: Find non-matching character in string from the end (public member function )

substr: Generate substring (public member function )

compare: Compare strings (public member function )

Non-member function overloads

operator+: Concatenate strings (function template )

relational operators: Relational operators for basic_string (function template )

swap: Exchanges the values of two strings (function template )

operator>>: Extract string from stream (function template )

operator<<: Insert string into stream (function template )

getline: Get line from stream into string (function template )

Member constants

npos: Maximum value of size_type (public static member constant )

C++

Reference

<string>

class templates:
- basic_string
- char_traits
classes:
- string
- u16string
- u32string
- wstring
functions:
- stod
- stof
- stoi
- stol
- stold
- stoll
- stoul
- stoull
- to_string
- to_wstring

std::basic_string

Template parameters

Template instantiations

Member types

Member functions

Non-member function overloads

Member constants

C++

Reference

C library:

Containers:

Input/Output:

Multi-threading:

Other:

<string>

class templates:

classes:

functions:

basic_string

member functions:

member constants:

non-member overloads: