// Kyle Thayer, CSE 142
// An example of value versus reference semantics.
import java.util.*;

public class ValueReferenceSemantics {
	public static void main(String[] args) {
   
      // Value semantics: With simple types (like ints), the
      // swap method wont change the values main has.
		int x0 = 7;
		int x1 = 35;
      System.out.println("before: x0 = " + x0 + ", x1 = " + x1);
      swap(x0, x1);
      // Values will not be swapped
      System.out.println("after: x0 = " + x0 + ", x1 = " + x1);
      System.out.println();
      
      // Reference semantics: With objects (like int[]), the
      // swapArray method will change the array that main has.
      // The array in main will be changed by the swapArray method.
      int[] x = {7, 35};
      System.out.println("before: x[0] = " + x[0] + ", x[1] = " + x[1]);
      swapArray(x);
      // Values will be swapped
      System.out.println("after x[0] = " + x[0] + ", x[1] = " + x[1]); 
      System.out.println();
   }
   
   // This method swaps the values of the two ints, x0 and x1 that 
   // were passed in. Since ints are passed by value, this will have
   // no effect on what main sees.
   public static void swap(int x0, int x1){
      int temp = x0;
      x0 = x1;
      x1 = temp;
   }
   
   // This method swaps the first two values in the array of ints (x)
   // that was passed in. Since the int[] is passed by reference, 
   // When main looks at the int[] after this method was called, it will
   // see that the values were swapped.
   public static void swapArray(int[] x){
      int temp = x[0];
      x[0] = x[1];
      x[1] = temp;
   }
   
   
}