greater

template <class T> struct greater;

Function object class for greater-than inequality comparison

This class defines function objects for the “greater than” inequality 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.

greater has its operator() member defined such that it returns true if its first argument compares greater than the second one using operator>, and false otherwise.

This class is derived from binary_function and is defined as: 

template <class T> struct greater : binary_function <T,T,bool> {
  bool 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.

// greater example

#include <iostream>
#include <functional>
#include <algorithm>
using namespace std;
 
int main () {
  int numbers[]={20,40,50,10,30};
  sort (numbers, numbers+5, greater<int>() );
  for (int i=0; i<5; i++)
    cout << numbers[i] << " ";
  cout << endl;
  return 0;
}

Output: 

50 40 30 20 10