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STRUCTURED PROGRAMMING IN THE SYMBOL-2R PROGRAMMING LANGUAGE

IP.com Disclosure Number: IPCOM000127989D
Original Publication Date: 1974-Dec-31
Included in the Prior Art Database: 2005-Sep-14
Document File: 19 page(s) / 70K

Publishing Venue

Software Patent Institute

Related People

Rodney Wayne Black: AUTHOR [+3]

Abstract

This paper is not intended as a tutorial on either structured programming or the SYMBOL-2R Programming Language (SPL). Instead, the intent is to convey to the reader those features of SPL which are important for using the structured programming methodology in writing programs in SPL. The first part of the paper gives a summary of struc-tured programming in which some of the reasons for writing well-structured programs are identified. Motivation is thus provided for many of the issues which are discussed in subse-quent parts. Part two gives a scanty overview of SPL, while parts three and four analyze SPL by examining how well its features match the main points raised in the discussion of structured programming. In order 1:o add coherency to this analysis, the primitives of SPL will be partitioned into two groups with a section devoted to each group; 7) data structures and related issues (part three); and 2) control sequencing constructs (part four). The following are of particular interest in both functional groups: 1) available SPL constructs conducive to structured pro-gramming; 2) available SPL constructs antithetical to structured programming; and 3) desirable, but non-available constructs.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

STRUCTURED PROGRAMMING IN THE SYMBOL-2R PROGRAMMING LANGUAGE

Rodney Wayne Black

1974 This report was submitted to the: Graduate Faculty at Iowa State University in partial fulfillment of requirements for the degree of Master of Science

STRUCTURED PROGRAMMING IN THE SYMBOL-2B PROGRAMMING LANGUAGE

Introduction

This paper is not intended as a tutorial on either structured programming or the SYMBOL-2R Programming Language (SPL). Instead, the intent is to convey to the reader those features of SPL which are important for using the structured programming methodology in writing programs in SPL. The first part of the paper gives a summary of struc-tured programming in which some of the reasons for writing well-structured programs are identified. Motivation is thus provided for many of the issues which are discussed in subse-quent parts. Part two gives a scanty overview of SPL, while parts three and four analyze SPL by examining how well its features match the main points raised in the discussion of structured programming. In order 1:o add coherency to this analysis, the primitives of SPL will be partitioned into two groups with a section devoted to each group;

7) data structures and related issues (part three); and 2) control sequencing constructs (part four). The following are of particular interest in both functional groups:

1) available SPL constructs conducive to structured pro-gramming;

2) available SPL constructs antithetical to structured programming; and

3) desirable, but non-available constructs.

I. Structured Programming: a brief overview A whole issue of Computing_Surveys (December 1974) was devoted to the question, "what is structured programming?" The answer arrived at is that no simple (or for that matter, complex) definition exists (p. 209) . A scan of the recent literature reveals no consensus even on the issues that fall under the heading of structured programming (8, 18 and 54). Denning noted that when the term was first used by Dijkstra and others, "they clearly intended it in the widest sense, encompassing notions of con_trol_structure_ ..., data structures ..., proper_documentation ..., and prqe2E control of the interface_With_the_WOrld" (9;p. 6). This overview will attempt to clarify that description by highlighting the major ideas endorsed by many proponents of structured pro-gramming. We begin the overview at some fundamental level, the task performed by a program, and watch the ideas develop. That do programs do? Abstractly, they transform a collection of things (data) into another collection of things (reports, payroll checks, graphs, control signals, etc.). A program is thus analogous to a production line which converts raw materials into refined products. Just as a production

Iowa State University Page 1 Dec 31, 1974

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STRUCTURED PROGRAMMING IN THE SYMBOL-2R PROGRAMMING LANGUAGE

line is a vehicle for transformation, so is a program. Jus...