/*
Jessica Miller, CSE 142, Autumn 2010
This program reverss an array of integers, demonstrating arrays as parameters
and reference semantics.
*/

import java.util.*;

public class Reverse {
    public static void main(String[] args) {
        //    index      0   1   2   3    4  5
        int[] numbers = {11, 42, -5, 27,  0, 89, 711};
        //               89, 0,  27, -5, 42, 11
		
		System.out.println(Arrays.toString(numbers));
		
		reverse(numbers);
		
		System.out.println(Arrays.toString(numbers));
	}
	
	// Reverses an integer array of numbers "in place".
	public static void reverse(int[] numbers) {
		for (int i = 0; i < numbers.length / 2; i++) {
			// i, numbers.length - 1 - i
			swap(numbers, i, numbers.length - 1 - i);
		}	
	}
	
	// Swaps any two elements in an array of integers.
	public static void swap(int[] nums, int index1, int index2) {
		int temp = nums[index1];
		nums[index1] = nums[index2];
		nums[index2] = temp;	
	}
}