// InsertionSort.java
//
// CS 101  Class Example

import java.util.*; // for Random number generator

public class InsertionSort {
    
    // --------- Main program---------------------------------------------
  
    public static void main(String[] args) {
	int n = 10; // default array size
    
	if (args.length > 0) {		   // if provided,
	    n = Integer.parseInt(args[0]); // get array size from command line
	}
    
	int[] a = new int[n];
	initArr(a);		// initialize array with random numbers

	System.out.println();
	System.out.print("Initial array: ");
	printArr(a);
	insertionSort(a);
	System.out.print("Sorted array:  ");
	printArr(a);
    }
  
    // --------- Insertion Sort ------------------------------------------

    public static void insertionSort(int[] a) {
	for (int i = 1; i < a.length; i++) {
	    insertIth(a, i);
	}
    }

    public static void insertIth(int[] a, int i) {
	// insert a[i] among sorted a[0] .. a[i-1]
	int val = a[i];
	int index = i-1;
	while (index >= 0 && val < a[index]) {
	    a[index+1] = a[index];
	    index--;
	}
	a[index+1] = val;
    }

    // --------- Helper Methods ------------------------------------------

    public static void initArr(int[] a) {
	// initialize array a with random numbers between 0 and 99
	Random rand = new Random(); 
	for (int i = 0; i < a.length; i++) {
	    a[i] = Math.abs(rand.nextInt()) % 100;
	}
    }

    public static void printArr(int[] a) {
	// print array a
	for (int i=0; i < a.length; i++) {
	    System.out.print(a[i] + " "); // print all elements on same line
	}
	System.out.println(); // print newline
    }
  
}