Re: Convert Alpha to Numeric

[Jim Langston <jlangston@xxxxxxxxxxxxxxxx>]

The way I have done it, if you can not just simply create a DS for it,
is to use the atof (Ascii to Float)  or atol (Ascii to Long) C APIs.
Here is an example using atol which is for integers.  Notice the
first two lines are commented out, but are your prototype for the
atof function.

D*atof            PR             8F   ExtProc('atof')
D*String                          *   Value Options(*String)
D
D atol            PR            10I 0 ExtProc('atol')
D                                 *   Value Options(*String)

D Invoice         S             11A   INZ('12345678901')
D InvoiceNo         S           11S 0

C                   Eval      InvoiceNo = atol(%Trim(TestInvOrCtr))

Limitations on this are the size of the Long Integer.  A Long Integer
is 4 bytes (I believe, it might be 8).  1 byte is a word, 2 bytes is an
integer, 4 bytes is a long integer.  But, on some systems, 2 bytes is
a short integer, 4 bytes is an integer and 8 bytes is a long integer.
You might have to experiment to find the size.

The range for a 4 byte integer is -2,147,483,648 to 2,147,483,647.
The range for an 8 byte integer is plenty and will give you your 20
bytes.  If the atol will not give you enough bytes, consider breaking
up the value into two 10 character strings.  Take the atol of the first
string (left side, most significant digits) and multiply it by 10^10 or
1,000,000,000 and add the second value of the other right side.
Or, declare a data structure as 20 numeric, and subdivide it into
2 other numerics 10 long.  Then just plug each side in.

Thinking on this, however, you can only use 9 digits.  It does not
go up to 9,999,999,999 but only 2,147,483,647.  So only 9 characters
are guaranteed accurate.  2 9 character numbers and a 2 character
number maybe.

Then again, consider just going through each character of the string and
if it is a space put in a 0.  Then just read it as a number.

-----------------------------------------------------------------------------

Floats can be easier, since a floating value can hold a larger number by far,
but can also be harder, since you can loose significant digits without even
being aware of it.  I believe the largest number of digits a float will hold
without loosing precision is 15 places.  You 10, 3 is 13 places, so it should
fit.  Just try the maximum and minimum numbers and a few places inbetween
after you build yoru function to test it.

Good luck,

Regards,

Jim Langston

There go a few more million brain cells.



"Baltus, Kevin" wrote:

>
>
> Hello.  I may be asking a basic question but what is the best way to convert 
>an alpha field into a numeric?  In my situation I have a 20-Alpha where the 
>values are whole numbers.  I need to get that whole number into a 10.3 field.
>
> Any suggestions would be greatly appreciated!  Thanks!

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