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Returning arrays

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Join Date: Nov 2007

Posts: 19

Reputation: Artmann is an unknown quantity at this point

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Artmann

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Newbie Poster

Returning arrays

Nov 12th, 2007

Hello.

I'm studying Pascal in school atm and have come over a bit of a problem with a program I've been asked to write.

The task is too make a calendar. My calendar uses an array with records too store data about the different days. The program uses a procedure to fill the global array with data.
Here comes the problem, my teacher don't like global variables being used inside procedures or functions.

As I come from a Java background I'm really frustrated over the fact that I can't find any simple way to convert my procedure to a function and return an array.

So I wonder if there is some hidden way to do this or some availabe extension to overcome this problem.

I would really appreciate some help.

-Signed Artmann

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Join Date: Oct 2007

Posts: 1,951

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Duoas

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Posting Virtuoso

Re: Returning arrays

Nov 12th, 2007

You most certainly can return arrays from functions. Here are two ways to solve your problem.

 Help with Code Tags 
 Delphi Syntax (Toggle Plain Text) 
program u;
{$APPTYPE CONSOLE}
uses
  SysUtils;
 
type
  tPerson = record
    name: string;
    age:  integer;
    end;
  tPeople = array of tPerson;
 
var people: tPeople;
 
//procedure getPeople( var result: tPeople );  // Method 1
function getPeople: tPeople;  // Method 2
  var
    s: string;
    i: integer;
  begin
  i := 0;
  repeat
    setLength( result, i+1 );
    write( 'Please enter a name> ' );
    readln( result[ i ].name );
    write( 'Please enter ', result[ i ].name, '''s age> ' );
    readln( result[ i ].age );
    write( 'Are there more (yes/no)? ' );
    readln( s );
    inc( i )
  until upCase( s[ 1 ] ) = 'N'
  end;
 
begin
// Method 1
//getPeople( people );
 
// Method 2
people := getPeople;
 
writeln( 'You entered ', length( people ), ' people.' )
end.
program u;
{$APPTYPE CONSOLE}
uses
  SysUtils;

type
  tPerson = record
    name: string;
    age:  integer;
    end;
  tPeople = array of tPerson;

var people: tPeople;

//procedure getPeople( var result: tPeople );  // Method 1
function getPeople: tPeople;  // Method 2
  var
    s: string;
    i: integer;
  begin
  i := 0;
  repeat
    setLength( result, i+1 );
    write( 'Please enter a name> ' );
    readln( result[ i ].name );
    write( 'Please enter ', result[ i ].name, '''s age> ' );
    readln( result[ i ].age );
    write( 'Are there more (yes/no)? ' );
    readln( s );
    inc( i )
  until upCase( s[ 1 ] ) = 'N'
  end;

begin
// Method 1
//getPeople( people );

// Method 2
people := getPeople;

writeln( 'You entered ', length( people ), ' people.' )
end.

Uncomment the method you want (the procedure/function body was written so that it will work with whichever header you uncomment).

The trick is that everything in Pascal must be strongly typed. Notice how the array itself has a specific type. Oh yeah, this is also a dynamic array...

Hope this helps.

Last edited by Duoas; Nov 12th, 2007 at 2:32 pm.