<string>

  • Article

Defines the container template class basic_string and various supporting templates.

For more information about basic_string, see basic_string Class

namespace std {
    template<class CharType>
        class char_traits;
    template<>
        class char_traits<char>;
    template<>
        class char_traits<wchar_t>;
    template<>
        class char_traits<char16_t>; 
    template<>
        class char_traits<char32_t>;

    template<
        class CharType,
        class Traits = char_traits<CharType>,
        class Allocator = allocator<CharType> 
    > class basic_string;

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

        // NARROW FUNCTIONS
    int stoi (
        const string& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    long stol (
        const string& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    unsigned long stoul (
        const string& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    long long stoll (
        const string& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    unsigned long long stoull (
        const string& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    float stof (
        const string& _Str, 
        size_t *_Idx = 0
    );
    double stod (
        const string& _Str, 
        size_t *_Idx = 0
    );
    long double stold (
        const string& _Str, 
        size_t *_Idx = 0
    );

    string to_string (long long _Val); 
    string to_string (unsigned long long _Val); 
    string to_string (long double _Val);

        // WIDE FUNCTIONS
    int stoi (
        const wstring& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    long stol (
        const wstring& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    unsigned long stoul (
        const wstring& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    long long stoll (
        const wstring& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    );
    unsigned long long stoull (
        const wstring& _Str, 
        size_t *_Idx = 0,
        int _Base = 10
    ); 
    float stof (
        const wstring& _Str, 
        size_t *_Idx = 0
    ); 
    double stod (
        const wstring& _Str, 
        size_t *_Idx = 0
    );
    long double stold (
        const wstring& _Str, 
        size_t *_Idx = 0
    );
    wstring to_wstring (long long _Val); 
    wstring to_wstring (unsigned long long _Val); 
    wstring to_wstring (long double _Val);

       // TEMPLATE FUNCTIONS
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator> operator+ (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator> operator+ (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const CharType *_Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator> operator+ (
            const basic_string<CharType, Traits, Allocator>& _Left,
            CharType _Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator> operator+ (
            const CharType *_Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator> operator+ (
            CharType _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );

    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator>&& operator+ (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const basic_string<CharType, Traits, Allocator>&& _Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator>&& operator+ (
            const basic_string<CharType, Traits, Allocator>&& _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator>&& operator+ (
            const basic_string<CharType, Traits, Allocator>&& _Left,
            const basic_string<CharType, Traits, Allocator>&& _Right
        );
    template<class CharType, class Traits, class Allocator> 
        basic_string<CharType, Traits, Allocator>&& operator+ (
            const basic_string<CharType, Traits, Allocator>&& _Left,
            const CharType *_Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator>&& operator+ (
            const basic_string<CharType, Traits, Allocator>&& _Left,
            CharType _Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator>&& operator+ (
            const CharType *_Left,
            const basic_string<CharType, Traits, Allocator>&& _Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_string<CharType, Traits, Allocator>&& operator+ (
            CharType _Left,
            const basic_string<CharType, Traits, Allocator>&& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator== (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator== (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const CharType *_Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator== (
            const CharType *_Left, 
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator!= (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator!= (
            const basic_string<CharType, Traits, Allocator>& left,
            const CharType *_Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator!= (
            const CharType *_Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator< (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator< (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const CharType *_Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator< (
            const CharType *_Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator>= (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator>= (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const CharType *_Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator>= (
            const CharType *_Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator> (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator> (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const CharType *_Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator> (
            const CharType *_Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator<= (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator<= (
            const basic_string<CharType, Traits, Allocator>& _Left,
            const CharType *_Right
        );
    template<class CharType, class Traits, class Allocator>
        bool operator<= (
            const CharType *_Left,
            const basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        void swap (
            basic_string<CharType, Traits, Allocator>& _Left,
            basic_string<CharType, Traits, Allocator>& _Right
        );
    template<class CharType, class Traits, class Allocator>
        basic_ostream<CharType>& operator<< (
            basic_ostream<CharType>& _OStream,
            const basic_string<CharType, Traits, Allocator>& _Str
        );
    template<class CharType, class Traits, class Allocator>
        basic_istream<CharType>& operator>> (
            basic_istream<CharType>& _IStream,
            basic_string<CharType, Traits, Allocator>& _Str
        );
    template<class CharType, class Traits, class Allocator>
        basic_istream<CharType, Traits>& getline (
            basic_istream<CharType, Traits>& _IStream,
            basic_string<CharType, Traits, Allocator>& _Str
        );
     template<class CharType, class Traits, class Allocator>
        basic_istream<CharType, Traits>& getline (
            basic_istream<CharType, Traits>& _IStream,
            basic_string<CharType, Traits, Allocator>& _Str,
            CharType _Delimiter
        );
     template<class CharType, class Traits, class Allocator>
        basic_istream<CharType, Traits>& getline (
            basic_istream<CharType, Traits>&& _IStream,
            basic_string<CharType, Traits, Allocator>& _Str
        ); 
     template<class CharType, class Traits, class Allocator>
        basic_istream<CharType, Traits>& getline (
            basic_istream<CharType, Traits>&& _IStream,
            basic_string<CharType, Traits, Allocator>& _Str,
            CharType _Delimiter
        );
}  // namespace std

Parameters

  • CharType
    The template parameter that describes the character data type.

  • Traits
    The template parameter that describes any properties of the CharType character data.

  • Allocator
    The template parameter that describes the stored memory allocator object.

  • _Str
    The basic_string that supports CharType character data.

  • _Val
    The value to be converted.

  • _Idx
    The index value of the first unconverted character.

  • _Base
    The number base to use.

  • _IStream
    The input stream that supports CharType character data.

  • _OStream
    The output stream that supports CharType character data.

  • _Delimiter
    The line delimiter.

  • _Left
    The first (left) compare parameter, either a basic_string or character data.

  • _Right
    The second (right) compare parameter, either a basic_string or character data.

Remarks

The C++ language and the Standard C++ Library support two types of strings:

  • Null-terminated character arrays often referred to as C strings.

  • Template class objects, of type basic_string, that handle all char-like template arguments.

Typedefs

string

A type that describes a specialization of the template class basic_string with elements of type char as a string.

wstring

A type that describes a specialization of the template class basic_string with elements of type wchar_t as a wstring.

u16string

A type that describes a specialization of the template class basic_string based on elements of type char16_t.

u32string

A type that describes a specialization of the template class basic_string based on elements of type char32_t.

Operators

operator+

Concatenates two string objects.

operator!=

Tests if the string object on the left side of the operator is not equal to the string object on the right side.

operator==

Tests if the string object on the left side of the operator is equal to the string object on the right side.

operator<

Tests if the string object on the left side of the operator is less than to the string object on the right side.

operator<=

Tests if the string object on the left side of the operator is less than or equal to the string object on the right side.

operator<<

A template function that inserts a string into the output stream.

operator>

Tests if the string object on the left side of the operator is greater than to the string object on the right side.

operator>=

Tests if the string object on the left side of the operator is greater than or equal to the string object on the right side.

operator>>

A template function that extracts a string from the input stream.

Specialized Template Functions

swap

Exchanges the arrays of characters of two strings.

stod

Converts a character sequence to a double.

stof

Converts a character sequence to a float.

stoi

Converts a character sequence to an integer.

stold

Converts a character sequence to a long double.

stoll

Converts a character sequence to a long long.

stoul

Converts a character sequence to an unsigned long.

stoull

Converts a character sequence to an unsigned long long.

to_string

Converts a value to a string.

to_wstring

Converts a value to a wide string.

Functions

getline

Extract strings from the input stream line by line.

Classes

basic_string Class

A template class that describes objects that can store a sequence of arbitrary character-like objects.

char_traits Struct

A template class that describes attributes associated with a character of type CharType

Specializations

char_traits<char> Struct

A struct that is a specialization of the template struct char_traits<CharType> to an element of type char.

char_traits<wchar_t> Struct

A struct that is a specialization of the template struct char_traits<CharType> to an element of type wchar_t.

char_traits<char16_t> Struct

A struct that is a specialization of the template struct char_traits<CharType> to an element of type char16_t.

char_traits<char32_t> Struct

A struct that is a specialization of the template struct char_traits<CharType> to an element of type char32_t.

Requirements

  • Header: <string>

  • Namespace: std

See Also

Reference

Thread Safety in the Standard C++ Library

Other Resources

Header Files