Pass By Value - Java Example Program

Pass By Value

CODE

class PassByValue
{
    public static void main(String s[])
    {
        int i = 5;
        System.out.println("i before increment : " + i);
        increment(i);
        System.out.println("i after increment : " + i);
    }
    
    public static void increment(int i)
    {
        System.out.println("i before increment in method : " + i);
        i++;
        System.out.println("i after increment in method : " + i);
    }
}

OUTPUT

i before increment : 5
i before increment in method : 5
i after increment in method : 6
i after increment : 5

DESCRIPTION

In this program we have defined a increment method and calling it from the main method. increment is the called method, where as the main is the calling method. Here we passed the parameter i using pass by value method. As we can see here the value of i is not changed in the main method. The value which is incremented to 6 in the method increment is not reflected in the calling method main. So, any changes done in the called method are not reflected in the calling method.

THINGS TO TRY

Change the return type of increment method from void to int and return the incremented value. In the main method, change the code increment(i); to i = increment(i);. Observe that the value incremented in the called method is now reflected in the calling method main.

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