Week1Mock1MCQ26

public class Main {
    
    
    // swap1, does work
    public static void swap1(int[] a1, int[] a2)
    {
        for (int i = 0; i < a1.length; i++)
        {
            int arrhold = a1[i];
            a1[i] = a2[i];
            a2[i] = arrhold;
        }
    }
    
    // swap2, does not work
    public static void swap2(int[] a1, int[] a2)
    {
        int[] arrhold = a1;
        a1 = a2;
        a2 = arrhold;
    }

    
    public static void main(String[] args) {
        
        // Harbor, Week 1, Mock 1, PR_PracticeTest_1.pdf
        
        // AP CS A 
        
        // MCQ 26
  
  
        int arr1[] = {1, 2, 3};
        
        int arr2[] = {7, 8, 9};
        
        for (int item: arr1)
        {
            System.out.print(item); 
            System.out.print(" ");
        }
        System.out.println();
  
        for (int item: arr2)
        {
            System.out.print(item); 
            System.out.print(" ");
        }
        System.out.println();
        
        System.out.println("arr1 and arr2 before swap1(arr1, arr2) \n");
        
  
        swap1(arr1, arr2);
        
        System.out.println("swap1(arr1, arr2) does work.");
        
        for (int item: arr1)
        {
            System.out.print(item); 
            System.out.print(" ");
        }
        System.out.println();
  
        for (int item: arr2)
        {
            System.out.print(item); 
            System.out.print(" ");
        }
        System.out.println("\n");
        
        swap2(arr1, arr2);
        
        System.out.println("swap1(arr1, arr2) does nothing.");
        
        for (int item: arr1)
        {
            System.out.print(item); 
            System.out.print(" ");
        }
        System.out.println();
  
        for (int item: arr2)
        {
            System.out.print(item); 
            System.out.print(" ");
        }
        System.out.println("\n");
        
  
    }
}