Dont understand Return Statement.

[ocean]

Evening all. I have problem understanding return. I made a simple thing to show what i mean.

public class test {

	public test() {
		init();
	}
	
	public int init() {
		int i = 10;
		return i;
	}
	
	public static void main(String[] args) {
		java.awt.EventQueue.invokeLater(new Runnable(){
			public void run(){
				new test();
			}
		}
);
	}

}

Can someone be nice and explain what return does. if im not all lost it return the value 10 to init()?

/ocean

[JosAH]

If a method returns a value the value is returned to the caller of the method; in your example the caller of the init() method is the constructor of the test class. Try this in your constructor: "System.out.println("init returned: "+init());" and see what happens.

kind regards,

Jos

[ocean]

Aaa, Then i dont need to call the method init(). i can just do this.

public class test {

	public test() {
		System.out.println("init returned: "+init(0));
	}
	
	public int init(int i) {
	        i = 10;
		return i;
	}
	
	public static void main(String[] args) {
		java.awt.EventQueue.invokeLater(new Runnable(){
			public void run(){
				new test();
			}
		}
);
	}

}

Am i Rigth?

[JosAH]

Yes you are right but you are calling the init( ... ) method from your constructor: it is part of the expression that is printed by System.out.println( ... ). If you don't call a method it can't return anything, simple as that ;-)

kind regards,

Jos

[ocean]

Thank you for the well explained lesson. But one more question. Can i only return 1 value? Exampel below dont work.

public int init(int i, int a) {
	    i = 10;
	    a = 20;
	   return i;
           return a;
	 }

How can that be solved?

EDIT. But i can return the value of ex. return i+a;

[literallyjer]

You can only return one value. If you want to return more than one, you would have to encapsulate the values into an object or use a collection (like an array or a list.)

Also, if you don't plan on passing any values into your init() method you can re-write it like this:

public int init() {
    int i = 10;
    return i;
}

or more precisely:

public int init() {
    return 10;
}

[ocean]

Now i got it. Thank you. This question has followed me for a long time. :)