Is Digits

Summary

The following are the RPG/LE fully free-form definitions and instructions needed for using the Is Digits service procedure. This service procedure simply allows the caller to validate that a character string is all numeric digits—or not.

Rule of Thumb

Sometimes, having a service procedure is simply a means of making code more self-documenting (i.e., easier for others to understand).

By Dave Clark

Service Prototype

Place the following in a separate copybook for inclusion in both the caller and the service program source members.

**free

//==============================================================================
// Validates variable-length character string for digits only.
//   Returns a Boolean true/false value as a result.
//==============================================================================
dcl-pr GenUtl_isDigits  ind;
  pString               varchar(50) const;
end-pr;

Service Procedure

Place the following in a service program source member.

**free
ctl-opt NoMain AlwNull(*UsrCtl) Debug Option(*SrcStmt:*NoDebugIo)
        DatFmt(*ISO) TimFmt(*ISO);

//==============================================================================
// Validates variable-length character string for digits only.
//   Returns a Boolean true/false value as a result.
//==============================================================================
dcl-proc GenUtl_isDigits export;
  dcl-pi *n             ind;
    pString             varchar(50) const;
  end-pi;

  dcl-c GenUtl_Digits   '0123456789';

  if %len(pString) = *zero;            // if no supplied value
    return *off;                       // indicate not numeric
  endif;

  return (%check(GenUtl_Digits: pString) = *zero); // return result of check
end-proc;

Examples

See the Format Phone Number service procedure. See the Format Zip Code service procedure.