PROJECT $2$

Introduction

The purpose of this project component is to provide a first experience in the actual writing of

computer programs. Using a relatively simple introductory scripting language $($Python$),$ you will

create program code in an editor $($Notepad$),$ save it to your disk, and run it from the command

line prompt.

You will gain experience in planning, writing, debugging, documenting, and running simple

programs. Learning Python serves as a convenient stepping$-$stone to more complex

object$-$oriented languages, such as Java.

In this project, you will use online resources, including downloadable Python tools and tutorials.

Before writing programs, it is useful to plan the programming steps and actions by writing an

algorithm. An algorithm is a set of plain English language commands or steps, each of which is

then replaced by the appropriate command line for the programming language used. This

technique becomes less useful when using complex object$-$oriented languages such as Java,

but may be helpful in the early stages of learning to design programs. You will write algorithms

for your first two programming exercises in this project.

The project will be graded for completeness and correct functioning of programs.

Acquiring the Tools

Download and install Python version $2\mathrm{.}2$ or higher by following the instructions at the Python

download site.

The downloaded file will be called Python$-2\_2.$exe. After downloading, run this file to complete

the installation. You can view the installed components from your "Start" list.

Writing Algorithms

In the traditional approach to programming, the program is seen as a series of steps, which may

include branches and loops. A branch occurs when a program may go in two or more different

directions, depending upon a logical condition or a choice made by the user. A loop is a situation

where a particular step, or series of steps, may be repeated until a certain condition or choice

occurs.

The following simple example of an algorithm includes both elements, and describes a simple

program for performing addition or multiplication.

Step $1-$display the program name "Addition and Multiplication"

Step $2-$display the options menu $"($A$)$dd$,($M$)$ultiply$"$

Step $3-$request and store input of user choice A or M as "choice"

Step $4-$if "choice" does not equal $"$A$"$ or $"$M$",$ go to Step $9$

Step $5-$request and store the first number to be used as variable $x$

Step $6-$request and store the second number to be used as variable $Y$

Step $7-$if "choice" $="$A$"$ go to Step $11$

Step $8-$if "choice" $="$M$"$ go to Step $13$