class template
<functional>
std::less_equal
template <class T> struct less_equal;
Function object class for less-than-or-equal-to comparison
Binary function object class whose call returns whether the its first argument compares less than or equal to the second (as returned by 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 less_equal : 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 less_equal {
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;
};
Objects of this class can be used on standard algorithms such as sort , merge or lower_bound .
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 first argument compares less than or equal to the second (
x<=y).
Example
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// less_equal example
#include <iostream> // std::cout
#include <functional> // std::less_equal, std::bind2nd
#include <algorithm> // std::count_if
int main () {
int numbers[]={25,50,75,100,125};
int cx = std::count_if (numbers, numbers+5, std::bind2nd(std::less_equal<int>(),100));
std::cout << "There are " << cx << " elements lower than or equal to 100.\n";
return 0;
}
Output:
There are 4 elements lower or equal to 100.
See also
- equal_to
- Function object class for equality comparison (class template)
- not_equal_to
- Function object class for non-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)