OOPS in JAVA 4

OOPS in JAVA 4

Call-by-value and Call-by-reference

There are two ways to pass an argument to a method. 

Call-by-value:

In this approach copy of an argument value is pass to a method. Changes made to the argument value inside the method will have no effect on the arguments.

Call-by-reference:

In this reference of an argument is pass to a method. Any changes made inside the method will affect the agrument value.

NOTE : In Java, when you pass a primitive type to a method it is passed by value whereas when you pass an object of any type to a method it is passed as reference.

Example of call-by-value.

public class Test
{
    public void callByValue(int x)
    {
        x=100;
    }
    public static void main(String[] args)
    {
       int x=50;
        Test t = new Test();
        t.callByValue(x);	//function call
        System.out.println(x);
    }
    
}
Output : 50

Example of call-by-reference.

public class Test
{
    int x=10;
    int	y=20;
    public void callByReference(Test t)
    {
        t.x=100;
        t.y=50;
    }
    public static void main(String[] args)
    {
       
        Test ts = new Test();
        System.out.println("Before "+ts.x+" "+ts.y);
        ts.callByReference(ts);
        System.out.println("After "+ts.x+" "+ts.y);
    }
    
}
Output :
Before 10 20
After 100 50