can't run my program

[Amonijack]

hi, i have a small problem. ...
here :

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Memo1: TMemo;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure destroy(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.destroy(Sender: TObject);
var i: integer;
a:array[1..10] of integer;
begin
  for i:=1 to 10 do
  a[i]:=0;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
max,i,j,n,gr:integer;
s:string;
a:array[1..10] of integer;
begin
  for i:=0 to 10 do
    begin
      s:=Memo1.Lines[i];
      val(s,n,gr);
      j:=j+1;
      If gr=0 then
      a[j]:=StrToInt(Memo1.Lines[i]);
    end;
    for i:=1 to 10 do
    if a[i]>max then
    max:=a[i];
    Edit1.Text:=IntToStr(max);
    end;
end.

When i run my program, i'am seing this message :



help ?
thanks

[WingedPanther]

Does the error message happen immediately, or after you press the button?

[Amonijack]

When i pressed the button.

[WingedPanther]

j should really be initialized before using it, but it looks like it varies from 1 to 11, which will mean it's an invalid index in array a. Thus, the access violation.

Delphi has a really good debugger. It's worthwhile to set a breakpoint on the first line of your method and trace through it to see what line is causing the error.

[Amonijack]

i edited

begin
for i:=0 to 10 do
a[i]:=0;
end;

TO

begin
for i:=1 to 10 do
a[i]:=0;
end;

but when i compiled, i sow this message :



next, i presed OK and i sow this :



help ?

[WingedPanther]

I'm pretty sure your error is on this line:

      a[j]:=StrToInt(Memo1.Lines[i]);

Also, do you ever initialize the value of j?

You may want to try this:

procedure TForm1.Button1Click(Sender: TObject);
var
max,i,j,n,gr:integer;
s:string;
a:array[1..10] of integer;
begin
  for i:=0 to 10 do
    begin
      s:=Memo1.Lines[i];
      val(s,n,gr);
      j:=j+1;
      showmessage('i: '+inttostr(i)+', s: '+inttostr(s)+', gr: '+inttostr(gr)+', j: '+inttostr(j));
      If gr=0 then
      a[j]:=StrToInt(Memo1.Lines[i]);
    end;
    for i:=1 to 10 do
    if a[i]>max then
    max:=a[i];
    Edit1.Text:=IntToStr(max);
    end;

This will give you a debugging message and help you determine where the error is occurring and why.

[Amonijack]

I'm pretty sure your error is on this line:

      a[j]:=StrToInt(Memo1.Lines[i]);

Also, do you ever initialize the value of j?

You may want to try this:

procedure TForm1.Button1Click(Sender: TObject);
var
max,i,j,n,gr:integer;
s:string;
a:array[1..10] of integer;
begin
  for i:=0 to 10 do
    begin
      s:=Memo1.Lines[i];
      val(s,n,gr);
      j:=j+1;
      showmessage('i: '+inttostr(i)+', s: '+inttostr(s)+', gr: '+inttostr(gr)+', j: '+inttostr(j));
      If gr=0 then
      a[j]:=StrToInt(Memo1.Lines[i]);
    end;
    for i:=1 to 10 do
    if a[i]>max then
    max:=a[i];
    Edit1.Text:=IntToStr(max);
    end;

This will give you a debugging message and help you determine where the error is occurring and why.

I am seing this messages when i am trying to compile the program.

[Error] Unit1.pas(39): There is no overloaded version of 'IntToStr' that can be called with these arguments

[Fatal Error] Project1.dpr(5): Could not compile used unit 'Unit1.pas'

Some help ?

[WingedPanther]

Sorry, remove the one around s.

[Firebird_38]

Sorry, but this is just silly.
First off, the code in your "destroy" method does absolutely nothing. Secondly, your array a only contains 10 items, numbered 1 through 10, and you're COUNTING from 0 to 10. So no matter what you set j to, you're trying to fill more array elements than you have. Thus error.

Try:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Memo1: TMemo;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    //procedure destroy(Sender: TObject); REMOVE THIS
    //PLUS, if you're going to make a destroy, do THIS:
    //destructor Destroy; override;
    //destructor, not procedure. And override it. Call "inherited;" last in your destructor
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{ remove all this
procedure TForm1.destroy(Sender: TObject);
var i: integer;
a:array[1..10] of integer;
begin
  for i:=1 to 10 do
  a[i]:=0;
end;
}
procedure TForm1.Button1Click(Sender: TObject);
const
 linecount=11
 highestlinenum=linecount-1;
var
max,i:integer;
s:string;
a:array[0..highestlinenum] of integer; //note that I put a ZERO
begin
  for i:=0 to highestlinenum do a[i]:=StrToIntDef(Memo1.Lines[i],0);
 //please be advised you need 11 lines in the memo! Numbered from 0 to 10!!
{
    begin
      s:=Memo1.Lines[i];
      val(s,n,gr);
      If gr=0 then
      a[j]:=StrToInt(Memo1.Lines[i]);
      ===>else what??? a[j] is what??? a is not initialized (it's LOCAL, so if it's not
      ===>initialized here, it won't be initialized at all
    end;
}
    max:=a[0]; //initialize your max value, or it might start out
                    //with 13678736834 (random number)
    for i:=1 to highestlinenumdo
      if a[i]>max then  max:=a[i];
    Edit1.Text:=IntToStr(max);
    end;
end.

Now, this will work. Note that setting array values in a destructor is useless.
After all, the array is about to be destroyed anyway. And if you want to keep
data across method calls (object procedure/function calls), you have to create
FIELDS in the object, like so:

type
  TObj=class
    FNumbers:array[0..9] of integer;
    FTotal:integer;
    constructor Create;
    destructor Destroy; override;
    procedure Init;
    procedure Calc;
    procedure Show;

    //when making a form's CREATE and DESTROY, use the form's
    //OnFormCreate and OnFormDestroy events!
  end;

constructor TObj.Create;
var n:integer;
begin
 for n:=0 to high(FNumbers) {this is 10} do FNumbers[n]:=n;
 FTotal:=0;
 //you never have to init to 0 for fields
 ShowMessage('I have been created!!');
end;

destructor TObj.Destroy; override;
begin
 //there's nothing to free. Tell the world I'm dying.
 ShowMessage('Bye bye');

 inherited; //this calls the "destroy" from TObject, the parent type of this class
end; //now the object is freed (after end)

procedure TObj.Init;
var n:integer;
begin
 for n:=0 to High(FNumbers) do FNumbers[n]:=10+n*5;
 //this does nothing interesting, but "init" is different from "create"
 //again, for no particular reason
 FTotal:=0;
 //this is set to 0, in case someone reads it before calling something else.
end;

procedure Tobj.Calc;
var n:integer;
begin
 FTotal:=0; //don't forget this... :S For instance, if you call "calc" twice in a row...
 for n:=0 to high(FNumbers) do Inc(FTotal,FNumbers[n]); //look up "inc" in the help
end;

procedure UseSillyObject;
var o1,o2:TObj;
begin
 o1:=TObj.Create;
 o2:=TObj.Create;
 o1.Init;
 ShowMessage('o1 before:'+IntToStr(o1.FTotal));
 o1.Calc;
 ShowMessage('o1 after:'+IntToStr(o1.FTotal));
 o2.Calc;
 ShowMessage('o2 after calc (no init):'+IntToStr(o2.FTotal));
 o1.Free; //you don't have to create or free forms, but your own objects, you do.
 o2.Free;
end;

This is just a simple example. Try the help files for more info on how to program.