What's wrong with my program?

[Przemyslav]

Hello everybody. I want to write program which convert Degrees/Minutes/Seconds to decimal coordinates, but i have a problem with the code. I'm the new one with Lazarus and Delphi language.

My code:

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2. var A, B, C, obl1: Real;
3. begin
4.   A := StrToFloat(Edit1.Text);
5.   B := StrToFloat(Edit2.Text);
6.   C := StrToFloat(Edit3.Text);
7.   obl1 := (B/60)+(C/3600);
8.   Label1.Caption := FloatToStr(A) + ',' + FloatToStr(obl1);
9. end;  

When I input coordinates for example: 41°24'12.2 I have error.

My form and error in attachments.

Could you help? Thank you.

[Przemyslav]

Error:

[Handoko]

I tested your code, it worked on my computer without error.

Have you tried to use '12.2' and '12,2' ? I guess what you have is decimal separator issue, comma vs period.

Read more:
https://www.freepascal.org/docs-html/rtl/sysutils/strtofloat.html

[Przemyslav]

With "," it's okay but with "." i have this error. How to block to input "." in Edit?

[marcov]

With "," it's okay but with "." i have this error. How to block to input "." in Edit?

There is an allowedchars property iirc.

[loaded]

This is how i work ;

Code: Pascal  [Select][+][-]

1. procedure TForm1.FormCreate(Sender: TObject);
2. begin
3.   Application.UpdateFormatSettings := false;
4.   DecimalSeparator := '.';
5. end;
6.  
7.  
8. procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: char);
9. begin
10.   if not (Key in [#8, '0'..'9','-',DecimalSeparator]) then    Key := #0;
11. end;
12.        

[Przemyslav]

Thank you very much

[Bart]

A few remarks:

Use a TFloatSpinEdit instead of a TEdit. It is designed for what you seem to want.
It has a Value property (type Double), so you do not need to convert text to double yourself.
If the spinners of the control bother you, you can hide them (IIRC).

Alternatively use a TMaskEdit, so you have absolute control over the input.
With the correct mask, a user cannot even paste non-numbers into the control.

Instead of setting Application.UpdateFormatSettings to false, you can also use the string to floeat conversion routines with a TFormatSettings parameter.

Bart

[loaded]

Thank you so much for the information, bart.
Since different scenarios occur when it is necessary to write the data at hand to the file, I found such a solution in time.
But I made a note of what you said, I'll try it when it's convenient.

[Przemyslav]

Thank you everybody for help. Okay I will try to use TFloatSpinEdit