Program to demonstrate Heap Sort in C

Program to demonstrate Heap Sort in C 

/* array of MAXARRAY length ... */

#define MAXARRAY 5

/* preform the heapsort */

void heapsort(int ar[], int len);

/* help heapsort() to bubble down starting at pos[ition] */

void heapbubble(int pos, int ar[], int len);

int main(void) {

            int array[MAXARRAY];

            int i = 0;

            /* load some random values into the array */

            for(i = 0; i < MAXARRAY; i++)

                        array[i] = rand() % 100;

            /* print the original array */

            printf("Before heapsort: ");

            for(i = 0; i < MAXARRAY; i++)

            {

                        printf(" %d ", array[i]);

            }

            printf("\n");

            heapsort(array, MAXARRAY);

            /* print the `heapsorted' array */

            printf("After heapsort: ");

            for(i = 0; i < MAXARRAY; i++)

            {

                        printf(" %d ", array[i]);

            }

            printf("\n");

           

            return 0;

}

void heapbubble(int pos, int array[], int len)

{

            int z = 0;

            int max = 0;

            int tmp = 0;

            int left = 0;

            int right = 0;

           

            z = pos;

            for( ; ; )

            {

                        left = 2 * z + 1;

                        right = left + 1;

                        if(left >= len)

                                    return;

                        else if(right >= len)

                                    max = left;

                        else if(array[left] > array[right])

                                    max = left;

                        else

                                    max = right;

                        if(array[z] > array[max])

                                    return;

                        tmp = array[z];

                        array[z] = array[max];

                        array[max] = tmp;

                        z = max;

            }

}

void heapsort(int array[], int len)

{

            int i = 0;

            int tmp = 0;

            for(i = len / 2; i >= 0; --i)

                        heapbubble(i, array, len);

            for(i = len - 1; i > 0; i--)

            {

                        tmp = array[0];

                        array[0] = array[i];

                        array[i] = tmp;

                        heapbubble(0, array, i);

            }

}