Testing for numeric input

[Darren Reely]

Martyn,

Take a look at this hack. Its rough but I think it performs you 
requested function.

screen test-num
temp t_char varchar*7
define d_num float = nconvert(t_char); + (d_denum/100) ;&

title "test-num" centered
skip 4
field t_char label "testnum" pattern 
"((A|B|C|D|E|F|G|H)|(+|-)<(#)>.<#<#<)" upshift
field d_num label "rnum" picture " ^^^.^^" output scale 2 leading '-' 
display

procedure edit t_char
begin
if 'A' <= fieldtext[1:1] and 'H' >= fieldtext[1:1]
then warn = 'Letter ' + fieldtext + ' entered.'
if '+' = fieldtext[1:1] or '-' = fieldtext[1:1] or ('0' <= 
fieldtext[1:1] and '9' >= fieldtext[1:1])
then if d_num < -999.99 or d_num > 999.99
        then error "Number out of range."
        else warn = 'number = ' + formatnumber(d_num," 
###.##","-###.##","   0.00") ;&
end


Darren


Thomson, Martyn EDUC:EX wrote:

>     -----Original Message-----
>     From: Thomson, Martyn EDUC:EX [mailto:Martyn.Thomson@gems1.gov.bc.ca]
>     Sent: Tuesday, May 18, 2004 4:24 PM
>     To: POWERHOUSE NEW (E-mail)
>     Subject: Testing for numeric input
>
>     Hello listers,
>     Does anyone know of a simple way to test if the input to a text
>     field is numeric within a range -999.99 to +999.99 with the "+"
>     being optional.
>     Using NCONVERT(fieldtext) causes a data expression error when the
>     argument is not numeric.
>     I looked at matching against every possible pattern the user could
>     enter, but since the "-","+" and "." are optional on input, and
>     the range has be taken into account, the number of combinations
>     soon gets unmanageable.  
>     I could loop through each character matching against characters 0
>     to 9 , . - +  but then coding to ensure that the plus, negative
>     and period characters are in appropriate positions and not
>     repeated, also soon becomes lengthy.
>     There must be a more elegant method eh?
>
>     Regards,
>     Martyn Thomson
>     Ministry of Education, Victoria, BC
>      
>
>      
>