?
Solved

passing array as a parameter

Posted on 2004-04-12
1
Medium Priority
?
804 Views
Last Modified: 2010-04-05
hi, everyone.

my code is this:

procedure TForm1.Beregn(var Vinner: array of TKort);
var
j: integer;
begin
SetLength(Vinner,j);
dosomething with Vinner;
SetLength(Vinner,j);
end;

I call this metdhod this way:

procedure TForm1.Test;
var
Vinner: array of TKort;
begin
Beregn(Vinner);
Continue with my Vinner array that has been changed inside Beregn-method.
end;


But the thing is... I get an error everytime i try to call the SetLength method inside the Beregn method. Incompatible types, it says. Then I thought... is this a pointer-issue?
0
Comment
Question by:Darth_helge
[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
1 Comment
 
LVL 20

Accepted Solution

by:
Madshi earned 2000 total points
ID: 10804708
When using an open "array of" array parameter like that you can't change the length of the array. The reason is simple:

procedure TForm1.Test;
var Vinner: array [0..9] of TKort;
begin
  Beregn(Vinner);
end;

What should Delphi do now, if you call SetLength? Do you see the problem? That's why calling SetLength is not supported.

However, you can solve the problem this way:

type TVinnerArr = array of TKort;

procedure TForm1.Beregn(var Vinner: TVinnerArr);
var j: integer;
begin
  SetLength(Vinner,j);
  dosomething with Vinner;
  SetLength(Vinner,j);
end;

procedure TForm1.Test;
var Vinner: TVinnerArr;
begin
  Beregn(Vinner);
end;

This works.
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

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

The uses clause is one of those things that just tends to grow and grow. Most of the time this is in the main form, as it's from this form that all others are called. If you have a big application (including many forms), the uses clause in the in…
Have you ever had your Delphi form/application just hanging while waiting for data to load? This is the article to read if you want to learn some things about adding threads for data loading in the background. First, I'll setup a general applica…
Do you want to know how to make a graph with Microsoft Access? First, create a query with the data for the chart. Then make a blank form and add a chart control. This video also shows how to change what data is displayed on the graph as well as form…
Have you created a query with information for a calendar? ... and then, abra-cadabra, the calendar is done?! I am going to show you how to make that happen. Visualize your data!  ... really see it To use the code to create a calendar from a q…
Suggested Courses

771 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