class template
<functional>
std::not_equal_to
template <class T> struct not_equal_to;
Function object class for non-equality comparison
Binary function object class whose call returns whether its two arguments compare not equal (as returned by operator operator!=).
Generically, function objects are instances of a class with member function operator() defined. This member function allows the object to be used with the same syntax as a function call.
It is defined with the same behavior as:
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| template <class T> struct not_equal_to : binary_function <T,T,bool> { bool operator() (const T& x, const T& y) const {return x!=y;} };
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| template <class T> struct not_equal_to { bool operator() (const T& x, const T& y) const {return x!=y;} typedef T first_argument_type; typedef T second_argument_type; typedef bool result_type; };
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Objects of this class can be used on standard algorithms such as mismatch, search or unique.
Template parameters
- T
- Type of the arguments to compare by the functional call.
The type shall support the operation (operator!=).
Member types
| member type | definition | notes |
|---|
| first_argument_type | T | Type of the first argument in member operator() |
| second_argument_type | T | Type of the second argument in member operator() |
| result_type | bool | Type returned by member operator() |
Member functions
- bool operator() (const T& x, const T& y)
- Member function returning whether the arguments compare not equal (
x!=y).
Example
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| // not_equal_to example #include <iostream> // std::cout #include <functional> // std::not_equal_to #include <algorithm> // std::adjacent_find int main () { int numbers[]={10,10,10,20,20}; int* pt = std::adjacent_find (numbers, numbers+5, std::not_equal_to<int>()) +1; std::cout << "The first different element is " << *pt << '\n'; return 0; }
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Output:
The first different element is 20 |
See also
- equal_to
- Function object class for equality comparison (class template)
- greater
- Function object class for greater-than inequality comparison (class template)
- less
- Function object class for less-than inequality comparison (class template)
- greater_equal
- Function object class for greater-than-or-equal-to comparison (class template)
- less_equal
- Function object class for less-than-or-equal-to comparison (class template)