sort() function in C++

This tutorial covers the various built-in sort functions found in the C++ algorithm’s library. 

What Does C++ Sort Mean?

The concept of sorting in C++ entails rearranging an array's elements in a logical order. The hierarchy can be either highest to lowest or lowest to highest. Numerous issues can be resolved, including finding the minimum or maximum elements, etc., by sorting an unsorted array.

Sorting things out makes it simpler to analyze and look through the collection of elements for a specific element.

In internal sorting, the main memory, also known as RAM, contains the data that needs to be sorted, and the sorting process also takes place there. Internal sorting examples include bubble sort, insertion sort, and selection sort.

The data is frequently not in the RAM when sorting externally because of the size of the data. The RAM or main memory is thus gradually filled with data. The Merge sort is one instance of an external sort.

This tutorial will teach you how to sort an array using a built-in C++ function. It is incredibly quick; the worst-case time complexity is O(n*logn) to sort an array using the built-in merge sort or quick sort, which is much less time-consuming than any other sorting technique.

Built-in sort function in C++:

The algorithm header file's built-in function is used to sort containers like arrays and vectors in a specific order. Internally, Quick-sort is used to implement this function. A divide and conquer algorithm is quicksort. The lower elements and the higher elements are the first two smaller sub-lists that Quicksort creates from a larger list of elements. The sub-lists are then sorted recursively by Quicksort.

The following are the steps:

1. Choose a pivot, or random element, from the list (usually the last element).

2. The term "partition operation" describes the process of reordering the list's elements so that all items with values below the pivot appear first and all items with values above the pivot appear last.

3. Choose a pivot point in the sub-list once more, and then recursively sort the sub-lists of lesser and greater elements.

Lists of size 0 or 1 are the default cases for the recursion; as a result, by combining these lists, we can sort our list. This was the internal working of the sort function, we do not have to worry about it we can directly use the function and can get sorted values.

Syntax of sort function in c++

If we want to sort the array and let the array be arr with n elements then the syntax will be - 

sort(arr,arr+n)

This indicates that the array is being sorted from beginning to end. This function allows us to sort an array from any index to any index. If there is no definition, the array will be sorted in ascending order. [ Note - similarly we can sort string also]

If we want to sort the vector let vector be vec then the syntax will be -

sort(v.begin(),v.end())

Example 

Sorting array using inbuilt sort function c++ code:

#include <bits/stdc++.h>
using namespace std;


int main()
{
    int n=5;
  int a[n]={5,3,4,1,2};
  cout<<" array before sorting : ";
  for(int i=0;i<n;i++)
  cout<<a[i]<<" ";
  cout<<endl; 
  sort(a,a+n); // the inbuilt sort function 
  cout<<" array after sorting : ";
  for(int i=0;i<n;i++)
  cout<<a[i]<<" ";


    return 0;
}

Output :

array before sorting : 5 3 4 1 2 
array after sorting : 1 2 3 4 5