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procedure

7 replies on 1 page. Most recent reply: Mar 17, 2004 10:19 PM by Matt Gerrans

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Flat View: This topic has 7 replies on 1 page

anamika

Posts: 11
Nickname: anamika
Registered: Feb, 2004

procedure

Posted: Mar 14, 2004 8:07 AM

hi ,

Can we return more than one value in a procedure. if so how ?

twc

Posts: 129
Nickname: twc
Registered: Feb, 2004

Re: procedure

Posted: Mar 14, 2004 8:08 PM

Yes and No.

A method (as they are called in Java) can only return one thing. However, if that thing is an object, then, in a sense, it can return multiple items of data.

For example, a MouseEvent object is created in response to any of several mouse activities (i.e. clicking, moving, entering or exiting the space above a component). It has a method that can return a Point object that corresponds to the point where the event took place. A Point object has two fields, an x coordinate for the horizontal position, and a y coordinate for the vertical position.

So the getPoint() method is only returning one thing - a Point object. But that object contains both the x and y coordinates where the Mouse event occurred.

I hope this helps.
twc

Dhrubo

Posts: 32
Nickname: dhrubo
Registered: Mar, 2003

Re: procedure

Posted: Mar 15, 2004 6:35 AM

we can always return multiple values out of a procedure by returning a collection object as simple as that
dhrubo@indiainfo.com

twc

Posts: 129
Nickname: twc
Registered: Feb, 2004

Re: procedure

Posted: Mar 15, 2004 12:04 PM

> we can always return multiple values out of a procedure by
> returning a collection object as simple as that
> dhrubo@indiainfo.com

Either way you are still returning an object.

Coolest Head

Posts: 5
Nickname: stkovrflow
Registered: Mar, 2004

Re: procedure

Posted: Mar 15, 2004 8:52 PM

Or since all the variables are references(except the primitives) you can have out param in the calling parameter list.

example:

void foo(Object inParam, Object outParam1, Object outParam2)
{
outParam1 = new Integer(1);
outParam2 = new Integer(inparam.hasCode());
}

void main(String [] args)
{
Obj o1=new Object(),o2=null,o3=null;
foo(o1, o2, o3);
System.out.println(o2+","+o3);
}

Vincent O'Sullivan

Posts: 724
Nickname: vincent
Registered: Nov, 2002

Re: procedure

Posted: Mar 16, 2004 2:59 AM

> Or since all the variables are references(except the
> primitives) you can have out param in the calling
> parameter list.

You could do that but it would be an extraordinarily Bad Thing. I can't think of any reason I would allow such code to be delivered.

Vince.

Coolest Head

Posts: 5
Nickname: stkovrflow
Registered: Mar, 2004

Re: procedure

Posted: Mar 17, 2004 3:42 PM

> hi ,
>
> Can we return more than one value in a procedure. if so
> how ?

Actually I think I am wrong....

I cannot create a new object and expect it to come as an OutParam. I can only change an object. So just disregard my prev. comment.

Matt Gerrans

Posts: 1153
Nickname: matt
Registered: Feb, 2002

Re: procedure

Posted: Mar 17, 2004 10:19 PM

Yeah, I didn't think that example would work.

Nevertheless, you can "return" data with parameters, but as mentioned above, it's usually a bad idea:

public class AntiIdiom
{
   static void getOutaHere( StringBuffer name )
   {
      name.append("Outa here!");
   }
   public static void main( String [] args )
   {
      StringBuffer buffy = new StringBuffer();
      getOutaHere( buffy );
      System.out.println( "Got this: " + buffy.toString() );
   }
}

You could also create your own mutable object and mutate it like all get-out with every call. This is a good way to create code that is very "interesting" for others to read (just be sure that you don't sign your code when you do this).

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