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Problem with "readln" statement

Wed, 26 Mar 2003 13:11:07 -0700

basically what i want to do is have a limited field.
if i have a string[5] i should only be able to enter 5 characters in my
readln, but i can enter more than that. is there a way to limit it so u
can only type in 5 characters?

Re: Problem with "readln" statement

Wed, 26 Mar 2003 13:25:41 -0700

: basically what i want to do is have a limited field.
: if i have a string[5] i should only be able to enter 5 characters in my
: readln, but i can enter more than that. is there a way to limit it so u
: can only type in 5 characters?
:
Hey there. There is also another way of reading input from the keyboard. You can use Repeat Until Keypressed and then obtain the character pressed by assigning it to a variable (Press:=Readkey;). These commands are held in the Crt unit ;o) Hope that helps ya out.

Repeat
Repeat Until Keypressed;  {Wait for keypress}
Press:=Readkey;           {Obtain character}
Write(Press);             
Str:=Str+Press;           {Add character to String}
Until length(Str)=5;

-SteveXP- o(-_-)o

Re: Problem with "readln" statement

Wed, 26 Mar 2003 14:59:58 -0700

: Hey there. There is also another way of reading input from the keyboard. You can use Repeat Until Keypressed and then obtain the character pressed by assigning it to a variable (Press:=Readkey;). These commands are held in the Crt unit ;o) Hope that helps ya out.
:
:

: Repeat
: Repeat Until Keypressed;  {Wait for keypress}
: Press:=Readkey;           {Obtain character}
: Write(Press);             
: Str:=Str+Press;           {Add character to String}
: Until length(Str)=5;      
:

ReadKey is a blocking function, so you dont need that extra repeat until keypressed loop in there. It is actually a good idea to have it in conjunction with timeslice code though, since that'll stop your program from using 100% of the CPU.

Re: Problem with "readln" statement

Sat, 03 May 2003 12:27:21 -0700

: : Hey there. There is also another way of reading input from the keyboard. You can use Repeat Until Keypressed and then obtain the character pressed by assigning it to a variable (Press:=Readkey;). These commands are held in the Crt unit ;o) Hope that helps ya out.
: :
: :

: : Repeat
: : Repeat Until Keypressed;  {Wait for keypress}
: : Press:=Readkey;           {Obtain character}
: : Write(Press);             
: : Str:=Str+Press;           {Add character to String}
: : Until length(Str)=5;      
: :

:
: ReadKey is a blocking function, so you dont need that extra repeat until keypressed loop in there. It is actually a good idea to have it
in conjunction with timeslice code though, since that'll stop your program from using 100% of the CPU.
:
I think it doesn't work in this easy way, becouse you have to check
if the key is a valid character and the user must have a chance to edit his string.

Re: Problem with "readln" statement

Sat, 03 May 2003 17:24:15 -0700

FUNCTION GetString( MaxLength : Byte) : String;
VAR
   Key : Char;
   S : String;
Begin
     Repeat
           Key := Readkey;
           If Key = #8 Then
           Begin
                If Length(S) > 0 Then Dec(S[0]);
           End
           ELSE
           If (Length(S) <= MaxLength) AND    { Make sure it's not too long }
              Not(Key In[#10,#13,#27]) Then   { Make sure it doesn't }
              S := S + Key;                   { include Enter & ESC  }
     Until (Key = #13) or (Key = #27);
     If Key = #13 Then GetString := S
        ELSE GetString := '';
End;

This will do any string length up to 255. Below is code for a maximum length of 5 charaters.

 S := GetString(5);

Phat Nat