// Tyler Rigsby, CSE 142
// Code that emphasizes value semantics vs reference semantics

import java.util.*;

public class ValueReferenceSemantics {
	public static void main(String[] args) {
		int a = 7;
		int b = 35;
		
		int[] c = {4, 12};
	    
		String s = "";
		swap(7, 35, c, s);
		System.out.println("in main: a=" + a + ", b=" + b);
		System.out.println("c=" + Arrays.toString(c));
		
		int[] values = {3, 2, 1, 4, 5};
		reverse(values);
		System.out.println(Arrays.toString(values));
	}
	
	// Method to demonstrate value vs reference semantics...see inline comments
	public static void swap(int a, int b, int[] c, String s) {
		// swapping primitive variables like this is only reflected inside this method,
		// because the primitive types are passed-by-value
		int temp = a;
		a = b;
		b = temp;
		
		// changing values inside an array are reflected inside of main, because the array
		// is an object, so it is passed-by-reference. c in this method is thus a reference
		// to the same array as in main, so main can see our changes to that object
		temp = c[0];
		c[0] = c[1];
		c[1] = temp;
		
		// however, these operations aren't changing the object, they're changing the reference.
		// so these changes will be reflected in this method, but not back in main.
		c = new int[1];
		s = "hello";
				
		System.out.println("in method: a=" + a + ", b=" + b);
		System.out.println("c=" + Arrays.toString(c));
	}
	
	// takes an array as a parameter and reverses the order of the values in the array
	public static void reverse(int[] values) {
		for (int i = 0; i < values.length / 2; i++) {
			int temp = values[i];
			values[i] = values[values.length - (i + 1)];
			values[values.length - (i + 1)] = temp;
		}
	}
}