/** This program demonstrates the usage of arrays in Java
 *  @author A. T. Ozgelen
 */

import java.util.Arrays;

public class ArrayDemo {
    public static void main(String[] args) {
	// checking the size of an array using length. 
	if(args.length == 0) { 
	    System.out.println("Usage: java ArrayDemo <some text>"); 
	    System.exit(1);
	}

	// declaring an array 
	int[] intArray;             // this is considered to be the better form 
	double doubleArray[];       // this too is legal 

	// initializing an array 
	intArray = new int[10];                    // allocates the memory for 100 int values, all initialized to 0
	doubleArray = new double[] {1.2, 3.1, 5.0};   // allocates and initializes the values for 3 double types

	// accessing and printing elements of an array
	System.out.println("doubleArray:");
	for(int i = 0; i < doubleArray.length; i++) 
	    System.out.print(doubleArray[i] + " "); 
	System.out.println("\n");

	// using for(each) loop 
	System.out.println("intArray:");
	for(int elem: intArray)
	    System.out.print(elem + " "); 
	System.out.println("\n");	    
	
	// using toString() method of Arrays class
	System.out.println("intArray using .toString():");
	System.out.println(Arrays.toString(intArray) + "\n");

	// assigning an array to another just creates another reference to the same array,
	// in other words, it does not create another copy as might be expected!
	int[] otherIntArray = intArray; 
	intArray[2] = 5; 
	System.out.println("otherIntArray[2]:" + otherIntArray[2]);
	System.out.println("intArray using .toString():");
	System.out.println(Arrays.toString(intArray) + "\n");

	// making a copy of an array
	int[] copyIntArray = Arrays.copyOf(intArray, intArray.length);
	intArray[2] = 7; 
	System.out.println("intArray[2]:" + intArray[2]);
	System.out.println("copyIntArray[2]:" + copyIntArray[2]);
    }
}