import java.util.*;

public class ReverseArray {
	public static void main(String[] args) {
		int a = 12;
		int b = 15;
		
		// this method has no effect on a and be because 
		// ints use value semantics (copied into parameters)
		swap(a, b);
		System.out.println(a + " " + b);
		
		int[] nums = {12, 43, 65, 76, 38, 65};

		// this method reverses the array because
		// arrays are objects so are passed to methods
		// using reference semantics
		reverse(nums);
		System.out.println(Arrays.toString(nums));
	}
		
	// swaps the values of two variables
	// because of value semantics, only affects the local variables
	public static void swap(int a, int b) {
		int temp = a;
		a = b;
		b = temp;	
	}
	
	// reverses the order of values in an array
	public static void reverse(int[] nums) {
		// need to stop at half or we un-reverse
		for (int i = 0; i < nums.length / 2; i++) {
			int temp = nums[i];
			nums[i] = nums[nums.length - 1 - i];
			nums[nums.length - 1 - i] = temp;
		}	
	}
}