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CHAPTER 1

The Phases of Software Development

NOTE: The material in this presentation is a compilation from the Zybook of “Principles of Data Structure”, the book “Data Structures and other objects using C++” by Michael Main and Walter Savitvch, and original content from your professor.

By Prof. Rafael Orta, M.S.

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Agenda

NOTE: The material in this presentation is a compilation from the Zybook of “Principles of Data Structure”, the book “Data Structures and other objects using C++” by Michael Main and Walter Savitvch, and original material from your professor.

Data vs. Information
Planning, Analysis, Design, Implementation, Testing & Integration, Maintenance.
Running time Analysis.
Testing and Debugging.

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Data vs Information video

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Planning, Analysis, Design, Implementation, Testing & Integration, Maintenance.

Data Structures are organized collections of data.

The SDLC phases occur in all software.

Some of the phases can be combines and sometimes they do not execute in the order you see on the right (ex. Agile Development).

Most of the work does not depend on a particular programming language.

We will be using C++ in this class, you should should be aquainted with it, and top down design. There are resources in the professor website to help you get familiar with.

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Few Concepts

Algorithms: Set of instructions for solving a problem.

Pseudocode: Mix of English and a programming language used to write algorytms. It’s objective is to improve clarity.

Top Down: Breaking a problem into smaller problems or subtasks and then those subtasks into even smaller subtasks and so forth. Eventually the subtasks become so small that the implementation is trivial in a computer language.

Functions, methods or procedures: It is the implementation of the sub-tasks mentioned above, it is a group of programming sentences (code), that provides a particular functionality part of a larger program.

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SPECIFICATIONS

It is the “Precise description of the problem”

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Formulation of steps to solve a problem, generally written in English and / or pseudocode

Considerations to keep in mind during the design:

Potential for code re-use (Functions / Claases)

Information hiding

Pre-conditions
Post-conditions

Posibility of future changes to the program

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It is the process that transforms the design into a program.

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Live Demo

(Use of functions)

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On what phase of the SDLC you need to select a programming language?.

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A/ Implementation

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Top down design

Video

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Runing time analysis

How many steps there are to the bottom?.

1.- Walk down and keep a tally:

Make a mark in paper for each step and come

back up.

2689 steps down and 2689 steps up, 2689 marks, 3x2689 or 3n

2.- Walk down but let your friend keep the tally:

You go back up to report one more step.

3,616,705 Downwards, 3,616,705 upwards, 2689 marks =

7,236,099 operations = n+2(1 + 2 + …. + n) = n ̂ 2 + 2n

3.- Ask a friend to read the sign at the bottom.

Only 4 marks = 4 operations, one for each digit of 2689.

NOTICE: You do not messure the time but the number of operations

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Introduction to Big O Notation

Notation used to help identify the time complexity (effectiveness / performance) of an algorithm while comparing it to other, helps to abstract the equations shown previosly.

O(n) O(2n) O(2n+2)

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Intro to Big O Notation