C++ program to sort elements of the given array

Sort Elements of the Given Array in C++

Here, in this page we will discuss the program to sort elements of the given array in C++ programming language. We will discuss various algorithms to sort the given input array.

Method Discussed :

  • Method 1 : Using Naive Approach.
  • Method 2 :Using inbuilt sort() function.
  • Method 3 : Using heap sort.

Let’s discuss above methods one by one,

Method 1 :

  • Run a loop from 0 to n-1
  • Inside that loop run another loop from i+1 to n
  • Check if(arr[i]>arr[j])
  • Swap arr[i] with arr[j]

Method 1 : Code in C++

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

void sorted(int arr[], int n){

  for(int i=0; i<n-1; i++){
     for(int j=i+1; j<n; j++){ if(arr[i]>arr[j]){
             int temp = arr[i];
             arr[i] = arr[j];
             arr[j] = temp;
          }
     }
   }

   for(int i=0; i<n; i++)
      cout<<arr[i]<<" ";
}

int main(){

   int arr[] = {10, 89, 67, 45, 83, 9, 12};
   int n = sizeof(arr)/sizeof(arr[0]);

   sorted(arr, n);
}

Output

9 10 12 45 67 83 89

Method 2 :

  • Call inbuilt sort() function to sort the array
  • Pass arr, arr+n to the sort function.

Method 2 : Code in C++

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

void sorted(int arr[], int n){

   sort(arr, arr+n);

   for(int i=0; i<n; i++)
      cout<<arr[i]<<" ";
}

int main(){

   int arr[] = {10, 89, 67, 45, 83, 9, 12};
   int n = sizeof(arr)/sizeof(arr[0]);

   sorted(arr, n);
}

Output

9 10 12 45 67 83 89

Method 3 :

To sort any array into a logical order(using heap sort) following steps are followed :-

  • Convert the array into heap.
  • Now convert this heap into max heap.
  • As the heap is converted to max heap largest element in the list is stored in the root of the heap, replace it with the last item of the heap.
  • Now delete this node and reduce the size of heap by 1.
  • Follow these steps until the list is sorted.
C++ program to sort the given array

Method 3 : Code in C++

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

// To heapify a subtree rooted with node i which is
// an index in arr[]. n is size of heap
void heapify(int arr[], int n, int i)
{
    int largest = i; // Initialize largest as root
    int l = 2 * i + 1; // left = 2*i + 1
    int r = 2 * i + 2; // right = 2*i + 2

    // If left child is larger than root
    if (l < n && arr[l] > arr[largest])
      largest = l;

    // If right child is larger than largest so far
    if (r < n && arr[r] > arr[largest])
       largest = r;

   // If largest is not root
   if (largest != i) {
     swap(arr[i], arr[largest]);

   // Recursively heapify the affected sub-tree
   heapify(arr, n, largest);
  }
}

// main function to do heap sort
void heapSort(int arr[], int n)
{
     // Build heap (rearrange array)
    for (int i = n / 2 - 1; i >= 0; i--)
      heapify(arr, n, i);

     // One by one extract an element from heap
     for (int i = n - 1; i > 0; i--) {
    
     // Move current root to end
     swap(arr[0], arr[i]);

     // call max heapify on the reduced heap
     heapify(arr, i, 0);
   }

   for(int i=0; i<n; i++)
      cout<<arr[i]<<" ";
}

int main(){

   int arr[] = {10, 89, 67, 45, 83, 9, 12};
   int n = sizeof(arr)/sizeof(arr[0]);

   heapSort(arr, n);
}

Output

9 10 12 45 67 83 89