Fundamental Principles of Programming

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Fundamental Principles of Programming

• Pedro Davalos
• SEI Training
• Mar 22, 2006

2
Outline

• Background
• Introduction to Programming, GL, Options
• Basics
• Scripts, Variables, Functions, Operators, Flow
• Getting Started
• Example/Demo 1 C
• Example/Demo 2 Python

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Background Introduction

• Programming Languages Share Common Principles
• Principles Include Structure, Flow, I/O
• Programmers write Software
• Software is everywhere!
• data gather/storage, data process, analyze
  data/visualize, Robotics/AI, Controls, GUIs,
  Communication,

4
Background Programming Language Generations
New

• 5th GL AI, neural net, Logic
• Lisp, Prolog
• 4th GL GUI, Databases
• Matlab, Python, SQL
• 3rd GL Human Readable
• C, C, Java, Fortran, Cobol, Basic, Pascal
• 2nd GL Low-Level, Assembly Language
• 1st GL Low-Level, Machine Language

Old
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Background Programming Language Generations

• Newer GLs
• PROS
• More logic-oriented
• More structure is built into the language built
  in functions
• Easier implementation (Less typing, Quicker
  learning)
• More graphical
• CONS
• Less control over bit manipulation
• More limited you are by the built in functions
  Inefficient Algorithms
• Not optimized for performance (timing and
  resources)

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Programming Language Comparison Study
Source Lutz Prechelt ( http//page.mi.fu-berlin.d
e/prechelt )
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Background Programming Options

• Option to choose Environment and Language
• Select based on requirements
• Memory, performance, speed, size, libraries,
  hardware, power, resources, users/GUIs,
  development time, cost, maintenance, life, etc.

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Basics Scripts

• Source Code is always a clear ASCII text file,
  usually with file extensions that represent
  language
• .m .c .cpp .py etc
• Source Code needs to be compiled to be
  executable
• 4GL Compilers seem
• invisible
• Matlab, python, etc

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Basics C Compiler Flow

• http//www.tenouk.com/ModuleW.html

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Basics Variables (1)

• All Programming Languages use variables to access
  data and handle parameters (after 2GL).
• 4GL
• Variable declarations or var. dimension not
  required in Matlab
• Matlab Built-in Variables are overwriteable!
• 3GL
• C has 29 reserved keywords that can not be
  redefined
• Variables must be declared at start of block
  before use in C

C Reserved keywords
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Basics Variables (2)

• Memory
• float f
• f3.14

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Basics Variables (3)

• Memory
• int i, s4, t4, u0

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Basics User Functions

• Functions accept input arguments and return
  output arguments.
• Sometimes referred to as procedures.
• Most local variables are created when the
  function is called, and are destroyed on return
  from that function.
• In other words Functions operate on variables
  within their own workspace.

Applies to most Languages!
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Basics Operators

• Arithmetic , -, , /, \, , , (),
• Logical lt, gt, , , , ,

Syntax differences
Applies to most Languages!
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Basics Flow Control

• Loop constructs
• if, else, and elseif
• switch and case
• for
• while
• Control Constructs
• continue (next iteration in for and while)
• break (exit for or while)
• try catch (debug)
• return (exit function)

Applies to most Languages!
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Getting Started (for free!)

• C Compiler 1 TAMU
• oldschool.tamu.edu ? cisrequest.tamu.edu
• Putty terminal to access unix account via SSH
• Use unix gcc filename.c
• C Compiler 2 Cygwin
• Linux-like environment for Windows
• C Compiler 3 DJGPP
• GNU C compiler utilities for DOS
• Python Compiler
• python.ORG

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Example Problem

• Description
• Write Program to log GPS data
• GPS has serial interface (DB-9 connector, RS-232)

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Example Approach

• Open/configure Socket
• While Running
• Read Line from GPS
• Write Line to file
• Close Socket

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Any Questions???
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References

• http//www.tenouk.com/ModuleW.html
• http//www.its.strath.ac.uk/courses/c/
• http//www.gnu.org/
• http//computer.howstuffworks.com/c.htm
• http//www.garmin.com/oem
• http//java.sun.com/
• http//cisrequest.tamu.edu
• http//python.org
• http//winscp.net
• http//www.pololu.com/projects/prj0003/
• Lutz Prechelt, An empirical comparison of C,
  C, Java, Perl, Python, Rexx, and Tcl,
  (http//page.mi.fu-berlin.de/prechelt)
• http//www.cygwin.com/