/* selection.c -- Read an integer array, print it, then sort it and
 * print it. Use the selection sort method.
 */

#include <stdio.h>

#define NMAX 10

int getIntArray(int a[], int nmax, int sentinel);
void printIntArray(int a[], int n);
void selectionSort(int a[], int n);

int main(void) {
  int x[NMAX];
  int hmny;
  int who;
  int where;

  hmny = getIntArray(x, NMAX, 0);
  if (hmny==0)
    printf("This is the empty array!\n");
  else{
    printf("The array was: \n");
    printIntArray(x,hmny);
    selectionSort(x,hmny);
    printf("The sorted array is: \n");
    printIntArray(x,hmny);
  }
}

void printIntArray(int a[], int n)
     /* n is the number of elements in the array a.
      * These values are printed out, five per line. */
{
  int i;

  for (i=0; i<n; ){
    printf("\t%d ", a[i++]);
    if (i%5==0)
      printf("\n");
  }
  printf("\n");
}

int getIntArray(int a[], int nmax, int sentinel)
     /* It reads up to nmax integers and stores then in a; sentinel 
      * terminates input. */
{
  int n = 0;
  int temp;

  do {
    printf("Enter integer [%d to terminate] : ", sentinel);
    scanf("%d", &temp);
    if (temp==sentinel) break;
    if (n==nmax)
      printf("array is full\n");
    else 
      a[n++] = temp;
  }while (1);
  return n;
}


void selectionSort(int a[], int n)
/* It sorts in non-decreasing order the first N positions of A. It uses 
 * the selection sort method.
 */
{
  int lcv;
  int rh;      /*Elements in interval rh..n-1 are in their final position*/
  int where;   /*Position where we have current maximum*/
  int temp;    /*Used for swapping*/
  
  for(rh=n-1;rh>0;rh--){
    /*Find position of largest element in range 0..rh*/
    where = 0;
    for (lcv=1;lcv<=rh;lcv++)
      if (a[lcv]>a[where])
	where = lcv;
    temp = a[where];
    a[where] = a[rh];
    a[rh] = temp;
  }
}