Lazarus
Home
Help
TinyPortal
Search
Login
Register
Lazarus
»
Forum
»
Free Pascal
»
General
(Moderators:
FPK
,
Tomas Hajny
) »
[SOLVED] „Error: Constant and CASE types do not match‟ with string
Free Pascal
Website
Downloads
Wiki
Bugtracker
Mailing List
Lazarus
Website
Downloads (Laz+FPC)
Packages (OPM)
FAQ
Wiki
Bugtracker
IRC channel
Latest SVN
Mailing List
Other languages
Foundation
Website
Useful Wiki Links
Project Roadmap
Getting the Source
Screenshots
How to use the forum
About donations (wiki)
Bookstore
Computer Math and Games in Pascal
(preview)
Lazarus Handbook
Search
Advanced search
Recent
Enabling/disabling treevi...
by
wp
[
Today
at 10:34:12 pm]
Reading text file data in...
by
Bart
[
Today
at 10:27:26 pm]
Brook - Beginner trying t...
by
RedOctober
[
Today
at 09:56:53 pm]
Solved: Thread with CLI
by
ojz0r
[
Today
at 08:54:29 pm]
Code in If statement not ...
by
CarmichaelJohn
[
Today
at 08:50:15 pm]
Update individual row in ...
by
paweld
[
Today
at 08:45:39 pm]
TList<string> VS. TString...
by
JuhaManninen
[
Today
at 08:35:11 pm]
Online Package Manager
by
GetMem
[
Today
at 08:31:55 pm]
[Solved] 32 Bit vs 64 Bit...
by
Peter H
[
Today
at 08:06:18 pm]
Unlocking a Sqlite3 db-fi...
by
JanRoza
[
Today
at 07:38:43 pm]
« previous
next »
Print
Pages: [
1
]
Author
Topic: [SOLVED] „Error: Constant and CASE types do not match‟ with string (Read 4591 times)
CM630
Hero Member
Posts: 922
Не съм сигурен, че те разбирам.
[SOLVED] „Error: Constant and CASE types do not match‟ with string
«
on:
July 09, 2018, 03:31:48 pm »
Following code works right:
Code: Pascal
[Select]
[+]
[-]
procedure
TForm1
.
Button1Click
(
Sender
:
TObject
)
;
var
A
:
string
=
''
;
B
:
string
=
'B'
;
C
:
string
=
'C'
;
begin
A
:
=
B
;
case
A
of
'B'
:
ShowMessage
(
B
)
;
'C'
:
ShowMessage
(
C
)
;
end
;
end
;
But this code generates „Error: Constant and CASE types do not match‟.
Code: Pascal
[Select]
[+]
[-]
procedure
TForm1
.
Button1Click
(
Sender
:
TObject
)
;
var
A
:
string
=
''
;
B
:
string
=
'B'
;
C
:
string
=
'C'
;
begin
A
:
=
B
;
case
A
of
B
:
ShowMessage
(
B
)
;
C
:
ShowMessage
(
C
)
;
end
;
end
;
B and C are strings. I tryed to cast to cast them to strings, anyway, but still I get the same error?
Is it me doing sth. wrong?
«
Last Edit: July 09, 2018, 04:00:45 pm by CM630
»
Logged
Лазар 2,0,10; W10 or W7 64bit; FPC3,2,0; rev 63526
RayoGlauco
Full Member
Posts: 108
Beers: 1567
Re: „Error: Constant and CASE types do not match‟ with string
«
Reply #1 on:
July 09, 2018, 03:49:09 pm »
In the second example, you use variables as selectors, instead of constants (B is a variable; 'B' is a constant). You cannot use variables as selectors.
See
http://wiki.freepascal.org/Case
Logged
To err is human, but to really mess things up, you need a computer.
Thaddy
Hero Member
Posts: 10684
Re: „Error: Constant and CASE types do not match‟ with string
«
Reply #2 on:
July 09, 2018, 03:50:04 pm »
Needs a literal value, indeed.
Logged
Gammatester
Jr. Member
Posts: 69
Re: „Error: Constant and CASE types do not match‟ with string
«
Reply #3 on:
July 09, 2018, 03:50:20 pm »
You should read the second part of the error message 'Error: String expression expected'. The case labels must be constants (i.e. literals or true constants). Your construct would throw equivalent message even for integer variables. The following code does work:
Code: Pascal
[Select]
[+]
[-]
var
A
:
string
=
''
;
const
B
=
'B'
;
C
=
'C'
;
begin
A
:
=
B
;
case
A
of
B
:
writeln
(
B
)
;
C
:
writeln
(
C
)
;
end
;
end
;
Logged
CM630
Hero Member
Posts: 922
Не съм сигурен, че те разбирам.
Re: „Error: Constant and CASE types do not match‟ with string
«
Reply #4 on:
July 09, 2018, 03:57:15 pm »
Ok, thanks, I will rewrite it with
Quote
If... then.
Logged
Лазар 2,0,10; W10 or W7 64bit; FPC3,2,0; rev 63526
Print
Pages: [
1
]
« previous
next »
Lazarus
»
Forum
»
Free Pascal
»
General
(Moderators:
FPK
,
Tomas Hajny
) »
[SOLVED] „Error: Constant and CASE types do not match‟ with string
TinyPortal
© 2005-2018