Binary Heap in C - Sanfoundry

This is a C program to implement the binary heap. It constructs a maximum binary heap of given array elements. Maximum binary heap is one in which the every child node has value less than the value of the parent.

Here is the source code of the C Program. The C program is successfully compiled and run on a Windows system. The program output is also shown below.

```
/* C program to build a binary heap */
```
```
#include <stdio.h>
```
```
#include <stdlib.h>
```
```
#define MAX 20
```
```
void maxheapify(int *, int, int);
```
```
int* buildmaxheap(int *, int);
```
```
void main()
```
```
{
```
```
    int i, t, n;
```
```
	int *a = calloc(MAX, sizeof(int));
```
```
    int *m = calloc(MAX, sizeof(int));
```

    printf("Enter no of elements in the array\n");

```
    scanf("%d", &n);
```
```
    printf("Enter the array\n");
```
```
    for (i = 0; i < n; i++) {
```
```
        scanf("%d", &a[i]);
```
```
    }
```
```
    m = buildmaxheap(a, n);
```
```
    printf("The heap is\n");
```
```
    for (t = 0; t < n; t++) {
```
```
        printf("%d\n", m[t]);
```
```
    }
```
```
}
```
```
int* buildmaxheap(int a[], int n)
```
```
{
```
```
    int heapsize = n;
```
```
    int j;
```
```
    for (j = n/2; j >= 0; j--) {
```
```
        maxheapify(a, j, heapsize);
```
```
    }
```
```
    return a;
```
```
}
```

void maxheapify(int a[], int i, int heapsize)

```
{
```
```
    int temp, largest, left, right, k;
```
```
    left = (2*i+1);
```
```
    right = ((2*i)+2);
```
```
    if (left >= heapsize)
```
```
        return;
```
```
    else {
```

        if (left < (heapsize) && a[left] > a[i])

```
            largest = left;
```
```
        else
```
```
            largest = i;
```

        if (right < (heapsize) && a[right] > a[largest])

```
            largest = right;
```
```
        if (largest != i) {
```
```
            temp = a[i];
```
```
            a[i] = a[largest];
```
```
            a[largest] = temp;
```

            maxheapify(a, largest, heapsize);

```
        }
```
```
    }
```
```
}
```

Output

Enter no of elements in the array
5
Enter the array
7
5
9
3
2
The heap is :
9
5
7
3
2

Sanfoundry Global Education & Learning Series – 1000 C Programs.

Note: Join free Sanfoundry classes at Telegram or Youtube

Here’s the list of Best Books in C Programming, Data Structures and Algorithms.

« Prev - C Program to Implement Two Stacks in a Single Array

» Next - C Program to Implement Queue using Two Stacks

Next Steps:

Get Free Certificate of Merit in Data Structure I
Participate in Data Structure I Certification Contest
Become a Top Ranker in Data Structure I
Take Data Structure I Tests
Chapterwise Practice Tests: Chapter 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Chapterwise Mock Tests: Chapter 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Related Posts:

Buy Programming Books
Buy Computer Science Books
Practice Programming MCQs
Apply for Information Technology Internship
Buy Data Structure Books

Recommended Articles: