Heap Sort Using C language

Heap Sort

Heap sort is a one type of sorting algorithm.
Worst-case performance : O(n log n)
Best-case performance : Ώ(n), O(n log n)
Average-case performance : O(n log n)
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Code

/*****Heap sort*****/
#include<stdio.h>
//Function declaration
void manage(int *, int);
void heapsort(int *, int, int);
//Main function start
int main(){
 int arr[20]; 
 int i,j,size,tmp,k;
 
 //Taking the number of element
  printf("Enter the number of elements to sort : ");
 scanf("%d",&size);
 
 //Taking the elements from user
 for(i=1; i<=size; i++) {
   printf("Enter %d element : ",i);
   scanf("%d",&arr[i]);
   manage(arr,i);
 }
 j=size;
 for(i=1; i<=j; i++) {
   //Swap
   tmp=arr[1];
   arr[1]=arr[size];
   arr[size]=tmp;
   size--;
   
   //Function call for heap sort
   heapsort(arr,1,size);
 }
 printf("\nAfter sorting the elements are: ");
 size=j;
 for(i=1; i<=size; i++)
     printf(" %d ",arr[i]);
 return 0;
}

//Function definition
void manage(int *arr, int i){
 int tmp; 
 tmp=arr[i];
 while((i>1)&&(arr[i/2]<tmp)) {
   arr[i]=arr[i/2];
   i=i/2;
 }
 arr[i]=tmp;
}

//Function definition
void heapsort(int *arr, int i, int size){
 int tmp,j;
 tmp=arr[i];
 j=i*2;
 while(j<=size) {
   if((j<size)&&(arr[j]<arr[j+1]))
      j++;
   if(arr[j]<arr[j/2]) 
      break;
   arr[j/2]=arr[j];
   j=j*2;
 }
 arr[j/2]=tmp;
}

Output

Enter the number of elements to sort : 7
Enter 1 element : 8
Enter 2 element : 4
Enter 3 element : 6
Enter 4 element : 9
Enter 5 element : 11
Enter 6 element : 2
Enter 7 element : 5

After sorting the elements are:  2  4  5  8  6  9  11