HeapSort, C++ (gcc)

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//g++  7.4.0
//Heap Sort
//heapify, heapSort and printArray codes credit to Geeks For Geeks 
//template modifications,swap and test driver codes are created by Rezaul Hoque on April 1,2021
//please contact at jewelmrh@yahoo.com
#include <iostream>
using namespace std;
template <class T>
 void heapify(T arr[], int n, int i)
{
    int largest = i; 
    int l = 2 * i + 1; 
    int r = 2 * i + 2; 
  
    
    if (l < n && arr[l] > arr[largest])
        largest = l;
  
    
    if (r < n && arr[r] > arr[largest])
        largest = r;
  
    
    if (largest != i) {
        swap(arr[i], arr[largest]);
  
        
        heapify(arr, n, largest);
    }
}
  
template <class T>
void heapSort(T arr[], int n)
{
    
    for (int i = n / 2 - 1; i >= 0; i--)
        heapify(arr, n, i);
  
    
    for (int i = n - 1; i >= 0; i--) {
        
        swap(arr[0], arr[i]);
  
        
        heapify(arr, i, 0);
    }
}
template <class T>
void swap(T& x, T& y)
{
T temp;
temp = x;
x=y;
y=temp;
}
template <class T>
 void printArray(T arr[], int n)
{
    for (int i = 0; i < n; ++i)
        cout << arr[i] << " ";
    cout << "\n";
}
  int main()
{
    int arr[] = { 7,6,5,4,3,2};
   char carr[]={'f','d','c','b','a'};
    int n = sizeof(arr) / sizeof(arr[0]);
  int n2=sizeof(carr)/sizeof(carr[0]);
cout<<"Before heap sort \n";
printArray(arr, n);
 printArray(carr,n2);

heapSort(arr, n);
  heapSort(carr,n2);
    cout << "After heap sort \n";
    printArray(arr, n);
 printArray(carr,n2);
return 0;
}

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Compilation time: 0.42 sec, absolute running time: 0.18 sec, cpu time: 0.01 sec, memory peak: 5 Mb, absolute service time: 0,67 sec