Centering a Text String

The RPG IV language introduces several powerful built-in functions that simplify string-handling requirements. You can add a few more string-related procedures to come up with a complete toolbox for processing text. The Centertext procedure centers a string field, a function that’s handy for centering headings on reports and displays.

Here’s the procedure code for Centertext:

  // ------------------------------------------------------------------
  // Procedure name - CenterText
  //
  // Centers a text string
  //
  // Return value:
  //      Centered text string (Char 256)
  //
  // Parameters:
  //      Input text string (Char 256)
  //      Length of result string (Unsigned 5.0)
  //                (Optional...defaults to 256)
  //
  // Usage example:
  //      Heading = CenterText('ABC Company':80);
  //
  // ------------------------------------------------------------------
H Copyright('(c) Copyright 2003, Bryan Meyers -- www.bmeyers.net')
H NoMain

  // ------------------------------------------------------- Prototypes
D CenterText      PR           256
D                              256    Value
D                                5U 0 Value Options(*NoPass)

  // --------------------------------------- Begin procedure CenterText
P CenterText      B                   Export
D CenterText      PI           256
D   InStr                      256    Value
D   StrLen                       5U 0 Value Options(*NoPass)

  // --------------------------------------------------- Work variables
D OutStr          S            256
D Pos             S              5U 0

 /FREE
  If %Parms = 1;
    StrLen = 256;
  Endif;

  If StrLen > (%Len(%Trim(InStr)) + 1);
    Pos = (StrLen - %Len(%Trim(InStr)))/2 + 1;
    %Subst(OutStr:Pos) = %Trim(InStr);
    Return OutStr;
  Else;
    Return InStr;
  Endif;
 /END-FREE

P CenterText      E

To use the Centertext procedure, a calling procedure must include the following prototype:

  // ------------------------------------------------------- Prototypes
D CenterText      PR           256
D                              256    Value
D                                5U 0 Value Options(*NoPass)

When you want to center a text string, you can include the procedure call in an assignment expression. One or two parameters are necessary:

• the text to be centered (may be an expression)
• the length of the string in which to center the text (defaults to 256 characters)

The procedure returns a 256-byte value, with the text centered in the length you specify:

Heading = Centertext('Company: ' + Cpyname : 80);

When you bind the program, be sure to include the module or service program that contains the Centertext procedure:

CRTPGM PGM(library/program) MODULE(library/program library/CENTERTEXT)