intro to prog

An Introduction to Program Design

CISPROG 1

Hegeman

Chapter 1: An Introduction to Java and Program Design 2

Introduction

• A program is a step-by-step series of instructions for a computer

• Computer programming is the process of writing these instructions

• Programmers, or developers, design and write programs using a programming language or development tool

• Java is a programming language that provides the structure for efficient and economical programs


Programming a Computer

• Companies need developers to build general application software packages

• Custom applications are built for specific needs

• Existing programs need maintenance, monitoring, and upgrades

• New applications will be needed due to emerging technologies


Program Development Cycle


Phase 1 – Analyze the Requirements• Verify that the requirements are clear and

complete

• Evaluate the problem to determine that it is solvable using a program

• List the required input and output data

• Determine whether the input data is available for testing


Phase 1 – Analyze the Requirements• Ensure that a solution, or algorithm, can

be developed with the information provided in the requirements

• Verify the user interface specifications


Phase 2 – Design the Solution

• Develop a logical model that illustrates the sequence of steps you will take to solve the problem

• Use design tools such as storyboards, class diagrams, flowcharts, and pseudocode to outline the logic of the program



• Storyboards are sketches of the user interface



• Class Diagrams illustrate the attributes and methods of a class of objects– Attributes define the characteristics of a class– Methods are instructions a class uses to

manipulate values, generate outputs, or perform actions



• Flowcharts graphically represent the logic used to develop an algorithm

• Control structures allow the programmer to specify the code that will execute only if a condition is met

• Flowcharts use pseudocode, English, or mathematical notation inside symbols to represent the steps of a solution



• Pseudocode is an English representation of how the program code should be written


Phase 3 – Validate the Design

• The programmer steps through the solution with test data

• The user agrees that the program design solves the problem put forth in the requirements

• The user verifies that the initial requirements document contains all necessary requirements


Phase 4 – Implement the Design

• Write the code that translates the design into a program

• Create the user interface

• Create comments within the code that explains the purpose of the code

• Unit testing– Test the code as it is written

• Test related code


Phase 5 – Test the Solution

• Create a test plan with test cases of sample input data and expected output

• Perform integration testing to ensure that components interact correctly

• Test boundary values

• Document any problems– If results are unsatisfactory, a new iteration of

the development cycle begins


Phase 6 – Document the Solution

• Requirements documents, program design documents, user interface documents, and documentation of the code

• Test cases and proof of successful completion of testing

• Program code should be archived electronically

intro to prog

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