std::greater_equal in C++ with Examples

Last Updated : 01 May, 2020

The std::greater_equal is a member of the functional class (<functional.h>). It is used to generate results of comparisons that are similar to the operator(≥). The advantage of this function over the operator(≥) is that it use the strict total order to generate the result, as opposed to the operator(≥) which uses the partial order. It returns a boolean value depending upon the condition. It can be used for comparing integers, characters, or strings, etc.

Header File:

#include <functional.h>

Template Class:

template <class T> struct greater_equal {

  // Declaration of the
  // greater equal operation 
  bool operator() (const T& x, const T& y) 
       const 
  {
      return x>=y;
  }

  // Type of first parameter
  typedef T first_argument_type;

  // Type of second parameter
  typedef T second_argument_type;

  // The result is returned
  // as bool type
  typedef bool result_type;
};

Parameter: This function accepts the type of the arguments T, as the parameter, to be compared by the functional call.

Return Type: It return a boolean value depending upon condition (let a & b are 2 element):

True: If a is greater than equals to b.
False: If a is less than b.

Below is the illustration of std::greater_equal in C++:

Program 1:

// C++ program to illustrate greater_equal 
  
#include <algorithm> 
#include <functional> 
#include <iostream> 
using namespace std; 
  
// Function to print the array arr[] 
void printArray(int arr[], int N) 
{ 
  
    for (int i = 0; i < N; i++) { 
        cout << arr[i] << ' '; 
    } 
} 
  
// Driver Code 
int main() 
{ 
    int arr[] = { 1, 5, 8, 9, 6, 
                  7, 3, 4, 2, 0 }; 
  
    int N = sizeof(arr) / sizeof(arr[0]); 
  
    // Sort the array in decreasing order 
    sort(arr, arr + N, greater_equal<int>()); 
  
    // Print sorted array 
    printArray(arr, N); 
    return 0; 
} 

Output:

9 8 7 6 5 4 3 2 1 0

Program 2:

// C++ program to illustrate greater_equal 
  
#include <algorithm> 
#include <functional> 
#include <iostream> 
using namespace std; 
  
// Driver Code 
int main() 
{ 
  
    int arr[] = { 30, 40, -50, 60, -70, 
                  10, 20, -80, 90, 100 }; 
    int N = sizeof(arr) / sizeof(arr[0]); 
  
    // Print the number of elements less 
    // than 0 
    cout << count_if( 
        arr, arr + N, 
        bind2nd(greater_equal<int>(), 
                0)); 
    return 0; 
} 