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Books on RPG programming on Amazon. (more programming languages).

popular (well-rated or big-selling) RPG books on Amazon

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RPG programming

RPG or RPG IV is a native programming language for IBM's iSeries (aka AS400) minicomputer system. Its latest incarnation includes prototyped functions and procedures, static and dynamic binding, access to C routine libraries, dynamic link libraries, and fully recursive and re-entrant code.

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Overview

An RPG program typically starts off with a File Specification, listing all files being written to, read from or updated, followed by an Input Specification containing program elements such as Data Structures and dimensional arrays. This is followed by the Calculation Specification, which contains the actual meat of the code, and finally the Output Specifications which can be used to determine the layout of the report.

The major strength of RPG is known as "The Cycle": every RPG program executes within an implied loop, which can apply the program to every record of a file. Alternately, "The Cycle" can make an interactive program continue to run until explicitly stopped.

The other distinguishing characteristic of RPG is that it, to a far greater extent than COBOL or FORTRAN, is column-dependent.


The article above is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "RPG programming language".