RPG books, sample code, etc.

There is a lot of information on the internet about C and C++ and Java, JavaScript, and HTML etc. but, it is disorganized and scattered. Worse yet for RPG programmers (those who work on IBM's AS/400 = iSeries), there just isn't much at all.

On my Links page, I am not trying to list as many sites as possible, like some others I have seen, but only the best, most comprehensive, sites and, where there is a small site with somthing of value, I try to specify exactly what it is. If I can make the list useful to me, it could be good for you also. If you know of a great site that I have not yet found, please add it on. ( To stop the shameless spammers I just put a hold on new entries till I have verifyed that they are from a programmer, not a spammer. )

Times are changing. Today we may still have what were "back end" or "internal" or "in house" programmers and separate from them the internet or web site designer but, more and more, today, one person is doing both and though "back end" business programming is complex enough, ... and all the complexity of the layout design is "complex enough", they are starting to get mixed together creating "double trouble!"



I have built a data base for sample code and information that we have not been able to find elsewhere but feel sure many would like to see. I am adding to it as I discover things and hope you will also.

SQL is a nonprocedural or "set oriented" language and
HTML is a Markup Language

but, T-SQL and PL/SQL are procedural extensions to SQL, making it like Java, C/C++, PHP, Perl, VBA, and etc., where every little step is spelled out, where, unstructured code, with its goto's, exits, jumps, and etc., becomes a tangled web of "spagetti", on the average, taking twice as long figure out, modify or enhance and, the larger the program grows, the more often it is modified, the more disastrous it becomes. Software vendors and IT departments alike, know the all too real limitations of continually updating and enhancing their programs. The ability of a co. to survive may be affected by the professionalism of their programmers. or of their vendor's IT depts. Good structured code can keep IT costs down and prevent lost time that can cost it market share, even profitability. . .

"The most basic practice, for those programming in procedural languages, is to avoid the infamous goto statement—well structured and designed programs simply have little need for it. "Spaghetti code," riddled with gotos, is notoriously difficult to decipher." - 1 programmer's affirmation

The Sequence is the in-line "execute one line after another" code between loops and branches.
A branch is an if "do something" (else, "do another").
A loop is just a sequence that is repeated while some condition is true. ( or for a given count, etc. )

All too often programmers get lazy and don't think of the consequences. They insert some kind of "if X then exit", failing to see that they have just put one more nail in the coffin of a dying program which, if it is only one of many, could lead to the replacement of all the software and maybe hardware. If that happens, the programmers could soon be gone also, if not the whole company.

Consider that no one cares what won't happen. and 3 lines saying what won't happen is ever more a waste when 2 lines could have said, clearly, what will:
like

     if not [OK]
     exit, jump, iterate, goto, ... spagetti, spagetti;
     end if  
  // your code (???) //

instead, the clear and more concise (2 lines) structured alternative:

     if [OK]
  // your code //
     end if   

Wow, so much clearer and Obvious!



more notes from others:

"It's frequently necessary to thoroughly understand all the details of long-forgotten code. I've often had the challenge of trying to decipher another person's application - and I've also had the humbling experience of trying to understand code that I wrote years ago. ...
"I now believe that if it takes more than a moment to understand a code segment, either more documentation is in order or the program structure should be revised. If I have to get back into this code five years from now, I'll want to know exactly what everything does, and why - and I'll want to know it fast!
"All variable, constant, function, and source file names should be succinct and descriptive, and accurately reflect the purpose of the variable. Even the lowly loop index needs to be more than just "i", "j", "k", etc."

Also, imagine your anger if "i" is all you have to go on for finding a loop somewhere in a large program.
(As bad as "ii" or "jj" or "kk" is, at least there may be some hope of finding it.)

Finally, source code benefits from peer review. You may only need to clarify a few comments and make variable names more descriptive, but when a second pair of eyes finds fundamental implementation flaws at an early - and inexpensive - stage of development, the extra process is worth it.

JAVA Timeline

Year Month Event 1996 January Sun releases Java Development Kit 1.0 (JDK 1.0). 1997 February Sun releases Java Development Kit 1.1 (JDK 1.1). 1998 December Sun releases the Java 2 Platform with version 1.2 of the Software Development Kit (SDK 1.2). 1999 August Sun releases Java 2 Platform, Standard Edition (J2SE). 1999 December Sun releases Java 2 Platform, Enterprise Edition (J2EE). 2000 May Sun releases J2SE with version 1.3 of the SDK. 2002 February Sun releases J2SE with version 1.4 of the SDK. 2004 September Sun releases J2SE with version 5.0 (instead of 1.5) of the JDK. Applications, Applets, Servlets and JSP's: Since an applet runs within a browser on the client, it's not ideal for working with resources that run on the server, such as enterprise databases. To provide access to enterprise databases, many developers use the Enterprise Edition of the Java 2 Platform (J2EE) to create applications that are based on servlets. A servlet is a special type of Java application that runs on the server and can be called by a client, which is usually a web browser. The servlet works much the same way as the applet. The main difference is that the code for the application runs on the server. When a web browser calls a servlet, the servlet performs its task and returns the result to the browser, typically in the form of an HTML page. Apache Tomcat is the servlet container that is used in the official Reference Implementation for the Java Servlet and JavaServer Pages technologies jakarta.apache.org/tomcat To make it easy to store the results of a servlet within an HTML page, the J2EE specification provides for JavaServer Pages (JSPs). Most developers use JSPs together with servlets when developing server-side Java applications. JSP vs. Servlets A basic consideration is the ratio of markup to code: the more markup the greater the case for a JSP, and the more code the greater the case for a servlet. "Code" being content such as loops and conditionals that surround blocks of HTML. This sort of code cannot be locked away inside a bean, whereas much else can. In fact it is a design goal of JSP development to keep as much code as possible out of the page and in a bean or other class which is then referenced in the page. The code sections of a JSP can quickly become unmanageable and difficult to debug, especially since the compiler is working on the generated ".java" source file and not directly on the JSP. But for a page with simple server-side functionality, such as altering output based on a few request parameters, a JSP can be much simpler and quicker to build than a servlet. A spot check for jobs nationally on 8-10-2005 came up with 509 jobs mentioning servlets, 868 with JSP, 14 for jhtml-Dynamo, and 6,484 for java - just to put all the above paragarphs in perspective.

A new tool for an old concept:

AJAX (Asynchronous JavaScript and XML): aka "remote scripting" allows client-side
JavaScript to request data from a server without having to refresh the Web page.

---

   "The March of Progress"    ("return to basics")

   1980: C  
         printf("%10.2f", x); 

   1988: C++ 
         cout << setw(10) << setprecision(2) << showpoint << x; 

   1996: Java 
         java.text.NumberFormat formatter
            = java.text.NumberFormat.getNumberInstance();
         formatter.setMinimumFractionDigits(2);
         formatter.setMaximumFractionDigits(2);
         String s = formatter.format(x);
         for (int i = s.length(); i < 10; i++)   
             System.out.print(' ');
         System.out.print(s);

   2004: Java 
         System.out.printf("%10.2f", x);
  
                   ( from http://www.horstmann.com/ )