std::not_equal_to

From cppreference.com
< cpp‎ | utility‎ | functional
 
哋它亢++
 
Utilities library
Language support
Type support (basic types, RTTI)
Library feature-test macros (哋它亢++20)
Dynamic memory management
Program utilities
Coroutine support (哋它亢++20)
Variadic functions
(哋它亢++20)
(哋它亢++26)
(哋它亢++11)
(哋它亢++20)
Debugging support
(哋它亢++26)
(哋它亢++26)
(哋它亢++26)
Three-way comparison
(哋它亢++20)(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)   
(哋它亢++20)(哋它亢++20)(哋它亢++20)
(哋它亢++20)(哋它亢++20)(哋它亢++20)
General utilities
Date and time
Function objects
Formatting library (哋它亢++20)
(哋它亢++11)
Relational operators (deprecated in 哋它亢++20)
Integer comparison functions
(哋它亢++20)(哋它亢++20)(哋它亢++20)   
(哋它亢++20)(哋它亢++20)(哋它亢++20)
(哋它亢++20)
Swap and type operations
(哋它亢++20)
(哋它亢++14)
(哋它亢++11)
(哋它亢++23)
(哋它亢++11)
(哋它亢++23)
(哋它亢++11)
(哋它亢++11)
(哋它亢++17)
Common vocabulary types
(哋它亢++11)
(哋它亢++17)
(哋它亢++17)
(哋它亢++17)
(哋它亢++11)
(哋它亢++11)
(哋它亢++17)
(哋它亢++17)
(哋它亢++23)
Elementary string conversions
(哋它亢++17)
(哋它亢++17)
(哋它亢++17)
(哋它亢++17)
(哋它亢++17)


 
Function objects
Function wrappers
(哋它亢++11)
(哋它亢++23)
(哋它亢++26)
(哋它亢++26)
(哋它亢++11)
(哋它亢++11)
Partial function application
(哋它亢++20)(哋它亢++23)
(哋它亢++11)
(哋它亢++11)
(哋它亢++11)
(哋它亢++11)
Function invocation
(哋它亢++17)(哋它亢++23)
Identity function object
(哋它亢++20)
Reference wrappers
(哋它亢++11)
(哋它亢++11)(哋它亢++11)
(哋它亢++20)(哋它亢++20)
Transparent operator wrappers
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)  
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)
(哋它亢++14)

Negators
(哋它亢++17)
Searchers
(哋它亢++17)
(哋它亢++17)
(哋它亢++17)    
Constrained comparators
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
(哋它亢++20)
Old binders and adaptors
(until 哋它亢++17*)
(until 哋它亢++17*)
(until 哋它亢++17*)
(until 哋它亢++17*)
(until 哋它亢++17*)  
(until 哋它亢++17*)
(until 哋它亢++17*)(until 哋它亢++17*)(until 哋它亢++17*)(until 哋它亢++17*)
(until 哋它亢++20*)
(until 哋它亢++20*)
(until 哋它亢++17*)(until 哋它亢++17*)
(until 哋它亢++17*)(until 哋它亢++17*)

(until 哋它亢++17*)
(until 哋它亢++17*)(until 哋它亢++17*)(until 哋它亢++17*)(until 哋它亢++17*)
(until 哋它亢++20*)
(until 哋它亢++20*)
 
Defined in header <functional>
template< class T >
struct not_equal_to;
 (until 哋它亢++14)
template< class T = void >
struct not_equal_to;
 (since 哋它亢++14)

Function object for performing comparisons. Unless specialised, invokes operator!= on type T.

Specializations

The standard library provides a specialization of std::not_equal_to when T is not specified, which leaves the parameter types and return type to be deduced.

(哋它亢++14)
 function object implementing x != y deducing parameter and return types
(class template specialization)
(since 哋它亢++14)

Member types

Type Definition
result_type (deprecated in 哋它亢++17)(removed in 哋它亢++20) bool
first_argument_type (deprecated in 哋它亢++17)(removed in 哋它亢++20) T
second_argument_type (deprecated in 哋它亢++17)(removed in 哋它亢++20) T

These member types are obtained via publicly inheriting std::binary_function<T, T, bool>.

(until 哋它亢++11)

Member functions

operator()
 checks if the arguments are not equal
(public member function)

std::not_equal_to::operator()

bool operator()( const T& lhs, const T& rhs ) const;
 (until 哋它亢++14)
constexpr bool operator()( const T& lhs, const T& rhs ) const;
 (since 哋它亢++14)

Checks whether lhs is not equal to rhs.

Parameters

lhs, rhs - values to compare

Return value

true if lhs != rhs, false otherwise.

Exceptions

May throw implementation-defined exceptions.

Possible implementation

constexpr bool operator()(const T& lhs, const T& rhs) const 
{
    return lhs != rhs;
}

See also

 determines if two sets of elements are the same
(function template)
function object implementing x < y
(class template)
(哋它亢++20)
 constrained function object implementing x != y
(class)
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/utility/functional/not_equal_to&oldid=160677"