// Program  sorts an integer array using the selection sort technique
// Exercise 4.31 from D&D

#include <iostream.h>
#include <iomanip.h>

void selectionSort(int array[], int start_index, int end_index);
// sorts the array via the selection sort method

int findmin(int array[], int start_index, int end_index);
// finds the index of the minimum element in the array 

void printArray(int array[], int size);
// prints the array


main () 
{
  const int size = 15;
  int numbs[size] = {6,3,8,2,0,12,13,14,1,4,5,11,10,7,8};

  printArray(numbs, size);
  selectionSort(numbs, 0, size-1);
  printArray(numbs, size);
  return 0;
}

// sorts the array via the selection sort method
// takes an integer array to be sorted and two indices
// indicating the positions within the array to be sorted
void selectionSort(int array[], int start_index, int end_index)
{
  int temp, small_element_index;

  cout << "Entering selectionSort with start_index = " 
       << start_index << endl;
 
  if (start_index < end_index)
    {
      small_element_index = findmin(array, start_index, end_index);

      cout << "\t Switching element at position " << small_element_index 
	   << " with element at position " << start_index << endl;

      // switch the smallest element into the lowest position in array
      temp = array[small_element_index];
      array[small_element_index] = array[start_index];
      array[start_index] = temp;

      selectionSort(array, start_index + 1, end_index);
    }
}


// finds the index of the minimum element in the array 
int findmin(int array[], int start_index, int end_index)
{
  int imin = start_index, 
      min_element = array[start_index], i;
  for (i = start_index + 1; i <= end_index; i++)
    if (array[i] < min_element)
      {
	min_element = array[i];
	imin = i;
      }
  return imin;
}

// prints the array
void printArray(int array[], int size)
{
  int i;
  cout << "The array contains the following elements:" << endl;
  for (i = 0; i < size; i++)
    {
      cout << "[" << i << "]" << " = " << array[i] << endl;
    }
}