Namespaces
Variants
Views
Actions

operator==,!=,<,<=,>,>=(std::basic_string)

From cppreference.com
< cpp‎ | string‎ | basic string
 
 
 
std::basic_string
 
Compare two basic_string objects
template< class CharT, class traits, class Alloc >

bool operator==( const basic_string<CharT,Traits,Alloc>& lhs,

                 const basic_string<CharT,Traits,Alloc>& rhs );
(1)
template< class CharT, class traits, class Alloc >

bool operator!=( const basic_string<CharT,Traits,Alloc>& lhs,

                 const basic_string<CharT,Traits,Alloc>& rhs );
(2)
template< class CharT, class traits, class Alloc >

bool operator<( const basic_string<CharT,Traits,Alloc>& lhs,

                const basic_string<CharT,Traits,Alloc>& rhs );
(3)
template< class CharT, class traits, class Alloc >

bool operator<=( const basic_string<CharT,Traits,Alloc>& lhs,

                 const basic_string<CharT,Traits,Alloc>& rhs );
(4)
template< class CharT, class traits, class Alloc >

bool operator>( const basic_string<CharT,Traits,Alloc>& lhs,

                const basic_string<CharT,Traits,Alloc>& rhs );
(5)
template< class CharT, class traits, class Alloc >

bool operator>=( const basic_string<CharT,Traits,Alloc>& lhs,

                 const basic_string<CharT,Traits,Alloc>& rhs );
(6)
Compare a basic_string object and null-terminated array of T
template< class CharT, class traits, class Alloc >
bool operator==( const CharT* lhs, const basic_string<CharT,Traits,Alloc>& rhs );
(7)
template< class CharT, class traits, class Alloc >
bool operator==( const basic_string<CharT,Traits,Alloc>& lhs, const CharT* rhs );
(7)
template< class CharT, class traits, class Alloc >
bool operator!=( const CharT* lhs, const basic_string<CharT,Traits,Alloc>& rhs );
(8)
template< class CharT, class traits, class Alloc >
bool operator!=( const basic_string<CharT,Traits,Alloc>& lhs, const CharT* rhs );
(8)
template< class CharT, class traits, class Alloc >
bool operator<( const CharT* lhs, const basic_string<CharT,Traits,Alloc>& rhs );
(9)
template< class CharT, class traits, class Alloc >
bool operator<( const basic_string<CharT,Traits,Alloc>& lhs,  const CharT* rhs );
(9)
template< class CharT, class traits, class Alloc >
bool operator<=( const CharT* lhs, const basic_string<CharT,Traits,Alloc>& rhs );
(10)
template< class CharT, class traits, class Alloc >
bool operator<=( const basic_string<CharT,Traits,Alloc>& lhs, const CharT* rhs );
(10)
template< class CharT, class traits, class Alloc >
bool operator>( const CharT* lhs, const basic_string<CharT,Traits,Alloc>& rhs );
(11)
template< class CharT, class traits, class Alloc >
bool operator>( const basic_string<CharT,Traits,Alloc>& lhs, const CharT* lhs );
(11)
template< class CharT, class traits, class Alloc >
bool operator>=( const CharT* lhs, const basic_string<CharT,Traits,Alloc>& rhs );
(12)
template< class CharT, class traits, class Alloc >
bool operator>=( const basic_string<CharT,Traits,Alloc>& lhs, const CharT* rhs );
(12)

Compares the contents of a string with another string or a null-terminated array of CharT.

All comparisons are done via the compare() member function (which itself is defined in terms of Traits::compare()):

  • Two strings are equal if both the size of lhs and rhs are equal and each character in lhs has equivalent character in rhs at the same position.
  • The ordering comparisons are done lexicographically -- the comparison is performed by a function equivalent to std::lexicographical_compare.
1-6) Compares two basic_string objects.
7-12) Compares a basic_string object and a null-terminated array of CharT.

Contents

[edit] Parameters

lhs, rhs - strings whose contents to compare

[edit] Return value

true if the corresponding comparison holds, false otherwise.

[edit] Exceptions

1-6)
(none) (until C++14)
noexcept specification:  
noexcept
  
(since C++14)
7-12) (none)

[edit] Complexity

Linear in the size of the strings.