template <class T> struct less_equal;

<functional>

Function object class for less-than-or-equal-to comparison

This class defines function objects for the "less than or equal to" comparison operation (<=).

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 regular function call, and therefore it can be used in templates instead of a pointer to a function.

less_equal has its operator() member defined such that it returns true if its first argument compares lower than or equal to the second one using operator<, and false otherwise.

This class is derived from binary_function and is defined as:

template <class T> struct less_equal : binary_function <T,T,bool> {
  T operator() (const T& x, const T& y) const
    {return x<=y;}
};

Objects of this class can be used with some standard algorithms such as sort, merge or lower_bound.

Members

T operator() (const T& x, const T& y)

Member function returning the result of the comparison x<=y.

Example

// less_equal example
#include <iostream>
#include <functional>
#include <algorithm>
using namespace std;

int main () {
  int numbers[]={25,50,75,100,125};
  int cx = count_if (numbers, numbers+5, bind2nd(less_equal<int>(),100) );
  cout << "There are " << cx << " elements lower or equal to 100.\n";
  return 0;
}

Output:

There are 4 elements lower or equal to 100.

See also