Changing the values of variables in methods, Java [duplicate]

Answer 1

That's because when you declare

 public static void funk(int a, int[] b) 

The scope of the variable a is only that method. Then when you change the value, you are changing only the value of that variable in that method.

About the b. Thats a new object reference to the same array created in main, that's why it seems the value does change ( what is changing is the array object underneath )

But try this:

public static void funk(int a, int[] b) { 
    // create a new reference for b
    int[] c = new int[b.length];
    c[0] = b[0];
    b = c;

    // The same.
    b[0] = b[0] * 2; 
    a = b[0] + 5;
} 

When you do that you'll the the value of tiger didn't change either ( only the content of the new array c created in funk )

You can simulate the pass by ref using a wrapper. See this post.

_{Although I haven't got any comments about that}

EDIT Just for fun:

I have modified your code to use the wrapper posted above.

It looks pretty strange but looks like it works.

// By ref simulated.
public class Test {

    public static void funk(_ a, int[] b) { 
        b[0] = b[0] * 2; 
        a.s(  b[0] + 5 ) ;
    } 

    public static void main(String[] args) {
        _ bird = new _(10);
        int[] tiger = {7};

        Test.funk( bird , tiger );

        System.out.println("bird = " + bird );
        System.out.println("tiger = " + tiger[0] );

    }

}

Prints

bird = 19
tiger = 14

:-S