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Sort an array in descending order using sort() function in C++ STL

C++ STL - sort() function Example: In this article, we are going to learn how to sort array elements in Descending Order using sort() function of C++ - STL?
Submitted by IncludeHelp, on January 03, 2018

Given an array and we have to sort the elements in Descending Order using C++ STL sort() function.

sort() function

It is a built-in function of algorithm header file it is used to sort the containers like array, vectors in specified order.

Reference: http://www.cplusplus.com/reference/algorithm/sort/

To sort elements in Descending order, we need to pass a function as third parameter, we can use greater<>() function.

This function creates comparison between the elements and puts the greater (largest element) first and then we can get descending order sorted elements.

Syntax:

sort(first, last, camp/function);

Here,
first - is the index (pointer) of first element from where we want to sort the elements.
last - is the last index (pointer) of last element.
camp/function - a comparison function that will create comparison between the elements.

Example:

    Input:
    Array: 10, 1, 20, 2, 30

    Output:
    Sorted Array: 30, 20, 10, 2, 1

C++ program:

#include <iostream>
#include <algorithm>
using namespace std;

int main(){
	//declare and define an array
	int arr[]={10, 1, 20, 2, 30};
	
	//size of the array
	//total size/size of an element
	int size = sizeof(arr)/sizeof(int);
	
	//calling sort() to sort array elements
	sort(arr, arr+5, greater<>());
	
	//printing sorted elements
	cout<<"Sorted elements are: ";
	for(int i=0; i<size; i++)
		cout<<arr[i]<<" ";
	
	return 0;
}

Output

Sorted elements are: 30 20 10 2 1