How to manage part of a STRING?

[ShaunBebbers]

Hello,

I am looking at string manipulation, particularly in terms of deleting the last character from a string.

My routine is as follows:

Code:

3 PRINT "Enter your number"; n$; "c:\>_";
   4 LET a$=INKEY$:
        IF a$=n$ AND b$<>"" THEN GO TO 9:
        END IF
   5 IF a$=""
        THEN GO TO 4:
        END IF
   6 IF (CODE a$=8 OR CODE a$=12)
        AND LEN(b$)>0 THEN LET a$="":
        GO SUB 2000:
        GO TO 8:
        END IF
   7 IF CODE a$<48 OR CODE a$>57
        THEN GO TO 4:
        END IF
   8 LET b$=b$+a$:
        PRINT AT 1,4; b$; "_ ":
        LET a$=INKEY$:
        GO SUB 1000:
        GO TO 4
   9 REM Rest of programme from here

The clear keyboard buffer routing is as follows:

Code:

1000 IF INKEY$<>"" THEN GO TO 1000:END IF
1001 RETURN

And the "delete last character" routine is:

Code:

2000 LET c$="":
2001 IF LEN(b$)>1
        THEN LET c$=b$(0 TO LEN(b$)-1):
        END IF
2002 LET b$=c$:
        RETURN

It's the "delete last character" routine that I'm having trouble with. the b$(0 TO LEN(b$)-1) isn't doing what I'm expecting, i.e., if the contents of b$ are:

Code:

12345

I want c$ to be:

Code:

1234

and therefore be passed back to the b$ string before returning.

Many thanks for any help or advice.

Regards,

Shaun.