HEAPSORT USING C++

#include <iostream>

using namespace std;

// A function to heapify the array.
void MaxHeapify(int a[], int i, int n)
{
int j, temp;
temp = a[i];
j = 2*i;

  while (j <= n)
{
if (j < n && a[j+1] > a[j])
j = j+1;
// Break if parent value is already greater than child value.
if (temp > a[j])
break;
// Switching value with the parent node if temp < a[j].
else if (temp <= a[j])
{
a[j/2] = a[j];
j = 2*j;
}
}
a[j/2] = temp;
return;
}
void HeapSort(int a[], int n)
{
int i, temp;
for (i = n; i >= 2; i--)
{
// Storing maximum value at the end.
temp = a[i];
a[i] = a[1];
a[1] = temp;
// Building max heap of remaining element.
MaxHeapify(a, 1, i - 1);
}
}
void Build_MaxHeap(int a[], int n)
{
int i;
for(i = n/2; i >= 1; i--)
MaxHeapify(a, i, n);
}
int main()
{
int n, i;
cout<<"\nEnter the number of data element to be sorted: ";
cin>>n;
n++;
int arr[n];
for(i = 1; i < n; i++)
{
cout<<"Enter element "<<i<<": ";
cin>>arr[i];
}
// Building max heap.
Build_MaxHeap(arr, n-1);
HeapSort(arr, n-1);

// Printing the sorted data.
cout<<"\nSorted Data ";

for (i = 1; i < n; i++)
cout<<"->"<<arr[i];

return 0;
}