//Put together by stella, Nov 07, for the purposes of lab 11 (on arrays)

public class LabArray
{
  public static void main (String [] args)
  {
    // Sample arrays for testing the code
    int[] a = {};
    int[] b = {2};
    int[] c = {9, -1, 3, 6, -10};
    int[] d = {8,3,-21,1000,3112,12};
    
    
    // Testing code:
    System.out.println("Testing printArray()");
    System.out.print("Array a: ");
    printArray(a);
    
    System.out.print("Array b: ");  
    printArray(b);
    
    System.out.print("Array c: ");  
    printArray(c);  
    
    System.out.print("Array d: ");  
    printArray(d);
    
    System.out.println("------------------------------");
    
    System.out.println("Testing selectionSort()");
    selectionSort(a);
    System.out.print("array a sorted w/ selection sort: ");
    printArray(a);
    
    selectionSort(b);
    System.out.print("array b sorted w/ selection sort: ");
    printArray(b);
    
    selectionSort(c);
    System.out.print("array c sorted w/ selection sort: ");
    printArray(c);
    
    selectionSort(d);
    System.out.print("array d sorted w/ selection sort: ");
    printArray(d);
  }
  //---------------------------------------------------------------
  
  //Implements selection sort.
  //Here is the idea in this method of sorting: 
  //Scan the whole array to select the smallest value.
  //Exchange it with the value in the first position of the array.
  //Scan the rest of the array (all but the first value) to find the smallest value.
  //Exchange it with the value in the second position of the array.
  //Continue this process for each position in the array.
  //When complete, the array will be sorted.
  public static void selectionSort(int[] data) {
    int min;   //
    for (int index=0; index<data.length-1; index++) { //controls the position in the array
      //where the next smallest value will be stored.
      min = index;
      for (int i=index+1; i < data.length; i++) //find the smallest val in the rest of the array
         if (data[i] < data[min])
            min = i;
      }
      swap(data, min, index); //exchange the smallest value with the value stored at index
    
  }
  
  // Prints out the input array 
  public static void printArray(int [] a) {
    System.out.print("[");
    for (int i = 0; i < a.length; i++) {
      System.out.print(a[i]);
      if (i < (a.length - 1)) 
        System.out.print(", ");
    }
    System.out.println("]");
  }
  
  //Helper method to swap two values in the input array
  public static void swap(int[] a, int index1, int index2) {
    int temp = a[index1];
    a[index1] = a[index2];
    a[index2] = temp;
  }
  
  
}