Solved

Out Parameter in Recursive Function

Posted on 2008-10-28
7
1,293 Views
Last Modified: 2013-12-17
Hi,

I have a function that adds elements from tree to a list recursively.
I would like to put the list initialization inside the implementation of the function (There's no good reason, just to understand how)
and pass the list argument as out parameter.

The thing is when I do it I get the error saying I must assign value, because I only initialize the list the first time if it is null the else condition doesn't have initialization.
How should I write it.

Here's the pseudo code:

public func(Tree root, out IList list)
{
.....
if (root == null)
      return;
if (list == null)
      list = new List();
func(root.child,out list);
....
}

0
Comment
Question by:breezback
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
7 Comments
 
LVL 6

Expert Comment

by:RishadanPort
ID: 22827169
maybe instead use the ref key?

public func(Tree root, ref IList list)
{
.....
if (root == null)
      return;
if (list == null)
      list = new List();
func(root.child,ref list);
....
}
0
 
LVL 6

Accepted Solution

by:
RishadanPort earned 500 total points
ID: 22827171
the "out" key requires that in each function call, the "out" variable is changed.
0
 
LVL 6

Expert Comment

by:RishadanPort
ID: 22827180
0
 
LVL 6

Expert Comment

by:RishadanPort
ID: 23098989
I should get credit for this question, as the answer I specified is correct.
0
 
LVL 6

Expert Comment

by:RishadanPort
ID: 23126833
Thanks
0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

This document covers how to connect to SQL Server and browse its contents.  It is meant for those new to Visual Studio and/or working with Microsoft SQL Server.  It is not a guide to building SQL Server database connections in your code.  This is mo…
The article shows the basic steps of integrating an HTML theme template into an ASP.NET MVC project
In an interesting question (https://www.experts-exchange.com/questions/29008360/) here at Experts Exchange, a member asked how to split a single image into multiple images. The primary usage for this is to place many photographs on a flatbed scanner…

740 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question