Program to Demonstrate Call by Value and Call by Reference in Java (BlueJ)

Program to Demonstrate Call by Value and Call by Reference in Java (BlueJ)

A) Program to Demonstrate Call by Reference
code:

/***** PROGRAM TO DEMONSTRATE CALL BY REFERENCE *****/
public class CallByRef
{
   public static  int num1 = 100, num2 = 200;
    public static void main()
    {
         CallByRef cbr = new CallByRef();
        
        System.out.println("***** Program to demonstrate call by reference *****");
        System.out.println("Value of num1 before call to swap :"+cbr.num1);
        System.out.println("Value of num2 before call to swap :"+cbr.num2);
        System.out.println("***********************************************");
      
        swap(cbr); // calling swap method by reference
       
        System.out.println("Value of num1 after call to swap :"+cbr.num1);
        System.out.println("Value of num2 after call to swap :"+cbr.num2);
        System.out.println("***********************************************");
    }
    public static void swap (CallByRef cbr2)
    {
        int temp;
        temp = cbr2.num1;
        cbr2.num1 = cbr2.num2;
        cbr2.num2 = temp;
       
        System.out.println("Value of num1 in swap :"+cbr2.num1);
        System.out.println("Value of num2 in swap :"+cbr2.num2);
        System.out.println("***********************************************");
    }
}

OUTPUT:
***** Program to demonstrate call by value *****
Value of num1 before call to swap :100
Value of num2 before call to swap :200
***********************************************
Value of num1 in swap :200
Value of num2 in swap :100
***********************************************
Value of num1 after call to swap :200
Value of num2 after call to swap :100
***********************************************

A) Program to Demonstrate Call by Value

Code: 

/***** PROGRAM TO DEMONSTRATE CALL BY VALUE *****/
public class CallByVal
{
    public static void main()
    {
        int num1 = 100, num2 = 200;
        System.out.println("***** Program to demonstrate call by value *****");
        System.out.println("Value of num1 before call to swap :"+num1);
        System.out.println("Value of num2 before call to swap :"+num2);
       
        swap(num1, num2); // calling swap method by value
       
        System.out.println("Value of num1 after call to swap :"+num1);
        System.out.println("Value of num2 after call to swap :"+num2);
    }
    public static void swap (int num11,int num22)
    {
        int temp;
        temp = num11;
        num11 = num22;
        num22 = temp;
       
        System.out.println("Value of num1 in swap :"+num11);
        System.out.println("Value of num2 in swap :"+num22);
       
    }
   
}

OUTPUT:
***** Program to demonstrate call by value *****
Value of num1 before call to swap :100
Value of num2 before call to swap :200
Value of num1 in swap :200
Value of num2 in swap :100
Value of num1 after call to swap :100
Value of num2 after call to swap :200