5.c

#include <stdio.h>
  void swap(int *a, int *b) {
    int temp = *a;
    *a = *b;
    *b = temp;
  }
  
  void heapify(int arr[], int n, int i) {
    int largest = i;
    int left = 2 * i + 1;
    int right = 2 * i + 2;
  
    if (left < n && arr[left] > arr[largest])
      largest = left;
  
    if (right < n && arr[right] > arr[largest])
      largest = right;
  
    if (largest != i) {
      swap(&arr[i], &arr[largest]);
      heapify(arr, n, largest);
    }
  }
  
  void heapSort(int 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);
    }*/
  }

  void printArray(int arr[], int n) {
    for (int i = 0; i < n; ++i)
      printf("%d ", arr[i]);
    printf("\n");
  }
  
  int main() {
    int n; 
printf("Enter the no of elements ");
scanf("%d",&n);
    int arr[n];
printf("Enter the elements ");
    for(int i=0;i<n;i++){
         scanf("%d",&arr[i]);
     }
    heapSort(arr, n);
  
    printf("Sorted array is \n");
    printArray(arr, n);
  }