Re: Floating Point Question

[dhandy@xxxxxxxxxxx (Douglas Handy)]

Bill,

>In an RPG ILE program, I have a 14-byte alpha Field that contains the
>external representation of a floating point value, for example:
>+1.2345678E005.  How can I take this alpha field and convert it into a
>4-byte Floating Point Field (with the value 123456.78 in this example)?

Every system has a run-time library of functions used for C programs,
regardless of whether or not a C compiler is installed.  These
functions are callable from RPG IV programs, and can often give
premade (and tested) functions instead of writing your own.

To use them you just need to prototype the call to the C function and
then include the QC2LE binding directory on the compile so it can
resolve the prototype.

In this case, C has a function called "atof" (alpha to float) which
will convert an alpha string in the format you describe to an 8-byte
float return value..  You can assign this to a 4-byte float if you
wish and RPG will handle the conversion.

      H bnddir('QC2LE') 

      D atof            pr             8f   extproc('atof')
      D   ptr_to_char                   *   value options(*string)
 
      D char            s             10a   inz('-123.45')
 
      C                   eval      num = atof(%trimr(char)) 
 
If num is not a float field, it would be advisable to add half-adjust
to the eval to minimize the rounding errors of float to other numeric
types.

Doug
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