Heap Sort

src/headers/heap.h

#include <selection.h>
#ifndef HEAPSORT
#define HEAPSORT
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

char** hsort(unsigned int, char**);
void heapify(int, unsigned int, char**);
void prnTree(unsigned int, char**);

#endif

src/heap.c

#include <heap.h>
/**
 * This is an example of the heap sort.
 * one thing I never realised in the past is that it's more or less a glorified
 * bubble it just limits the number of bubble comparisons to log2(n) so very
 * quick.  It does have the advantage of in place sorting.
 * 
 */
char** hsort(const unsigned int count, char** values) {
 unsigned int i;
 char* tmp;
 while(count>0) {
  heapify(0, count, values); 
  tmp = values[--count];
  values[count] = values[0];
  values[0] = tmp;
 }
 return values;
}

void heapify(int index, unsigned int size, char** values) {
 char* tmp;
 unsigned int count, child = 2*index + 1;
 prnTree(size, values);
 for(count=0;child<size && count<2;child++) {
  count++;
  if(child<size) {
   heapify(child, size, values);
   if(strcmp(values[child], values[index])>0) {
    tmp=values[index];
    values[index]=values[child];
    values[child]=tmp;
   }
  }
 } 
}

void prnTree(unsigned int count, char** values) {
 unsigned int i;
 printf("[");
 for(i=0; i < count; i++) {
  printf("%s, ", values[i]);
 }
 printf("\b\b]\n");
}