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operator==,!=,<,<=,>,>=(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* rhs );
 (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.

Parameters

lhs, rhs - strings whose contents to compare

Return value

true if the corresponding comparison holds, false otherwise.

Exceptions

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

Complexity

Linear in the size of the strings.

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