Starting out with Python - Chapter 1 PPT

8/20/2019 Starting out with Python - Chapter 1 PPT

1/44

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley

STARTING OUT WITH

ythonythonFirst Editionby

Tony Gaddis

Chapter 1Introduction to Computers and Programming


2/44

1-2

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-2

1.1 Introduction

• People use computers at…

– School for writing papers, research, email, online classes, etc.

– Work for analyzing ata, make presentations, !usinesstransactions, communicating, control machines, etc.

– "ome for paying !ills, shopping online, communicating, playingcomputer games, etc.

What are some of the ways youWhat are some of the ways youuse computers?use computers?


3/44

1-#

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-#

1.1 Introduction

• $e%ices that are computers…

– &ell Phones

– iPo s – 'lack!erries – &ar na%igation system ()PS*

Can you think of some other devicesCan you think of some other devicesthat are computers?that are computers?


4/44

1-+

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-+

1.1 Introduction•

&omputers are esigne to o any o! thattheir programs tell them to o.

• program is a set of instructions that a

computer follows to perform a task. or e/ample0 icrosoft Wor an o!e Photoshop

• Programs are commonly referre to as

software .What software have you used?What software have you used?


5/44

1-

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-

1.1 Introduction

• Programmers or Software Developers arethe in i%i uals that create computersoftware.

• 3hey ha%e the training an skill to esign,create, an test computer programs.

What are some of the fields inWhat are some of the fields inwhich computer programs arewhich computer programs areused?used?


6/44

1-4


1.2 Hardware and Software

Concept:

The physical devices that acomputer is made of are referredto as the computer’s hardware.

The programs that run on acomputer are referred to assoftware.


7/44

1-5



Hardware• 3he physical e%ices that a computer is

ma e of are referre to as the computer6shardware.• computer is a system of e%ices that

work together.


8/44

1-7



Hardware &omputer System consists of0 – &entral Processing 8nit (&P8* – ain memory – Secon ary storage – 9nput e%ices – :utput e%ices

Figure 1-2 3ypical componentsof a computer system


9/44

1-;

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-;


Hardware&entral Processing 8nit (&P8*

3he &P8 is the part of a computer that runs the

programs.Without a &P8 a computer cannot run software.

Running or executing a program is the term use whenthe computer performs the tasks that the program tellsit to o.


10/44

1-1<

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-1<

1.2 Hardware and SoftwareHardware

=>9 &? Worl 6s first programma!le computer ? 'uilt in 1;+? $esigne to calculate artillery !allistic

ta!les for the 8.S. rmy? &P8 was 7 feet tall, 19 & computer(courtesy of 8.S. rmy "istoric &omputer 9mages*

Figure 1-4 la! technicianhol s a mo ernmicroprocessor (photo courtesy of 9ntel&orporation*


11/44

1-11



Hardwareain emory

? &onsi ere the computer6s work area

? &omputer stores the program that is running as well as theata

? &ommonly known as the random-access memory(RAM

? $ata is @uickly accesse? A is a %olatile type of memory? 8se for temporary storage? A is erase when computer is turne off


12/44

1-12


1.2 Hardware and SoftwareHardwareSecon ary Storage $e%ices

? 3ype of memory that can hol ata for long perio s of time.? Programs an important ata are store in secon ary storage

? Dis! drive is a common type of secon ary storage

– Data is stored by magnetically encoding it onto a circular dis – ost computers ha%e an internal isk ri%e – Some ha%e e/ternal isk ri%esB they are use to create !ackup

copies

? "loppy drives recor ata onto a small floppy isk

– "ol s only a small amount of ata – Slow to access ata – &an !e unrelia!le


13/44

1-1#

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-1#


HardwareSecon ary Storage $e%ices

? #S$ drives are small e%ices that plug into the computer6suni%ersal serial !us (8S'* port

– 9t oes not contain a isk – 3he ata is store on flash memory – lso known as memory sticks an flash ri%es – 9ne/pensi%e, relia!le, an small

? %ptical devices (&D or D'D – $ata is enco e as a series of pits on the isc6s surface – 8ses laser to enco e the ata – "ol s large amounts of ata – )oo me ium for creating !ackups


14/44

1-1+

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-1+

1.2 Hardware and SoftwareHardware9nput $e%ices

? ny ata the computer collects from people an from other e%icesis calle input.

? 3he har ware component that collects the ata is calle an input

device .? &ommon input e%ices are0 – Cey!oar – ouse – Scanner – icrophone

– $igital camera

Can you think of any other input devices?Can you think of any other input devices?


15/44


16/44

1-14



Software

? =%erything a computer oes is controlle !ysoftware.? 3wo categories of software0

? System software

? pplication software


17/44

1-15


1.2 Hardware and SoftwareSoftwareSystem Software? Programs that control an manage the !asic operations of a

computer are referre to as system software .? 9nclu es the following types0

? %perating System controls the internal operations of the computer6shar ware an manages all of the e%ices connecte to the computer.

? #tility Programs perform a specialize task that enhances thecomputer6s operation or safeguar s ata.

? Software Developments ools are programs that are use to create,mo ify, an test software.


18/44

1-17


1.2 Hardware and SoftwareSoftware

pplication Software? Programs that people normally spen most of their time running on their

computers performing e%ery ay tasks are referre to as applicationsoftware .

? or e/ample0?

Wor processing? Sprea sheet? $ata!ase? Presentation

Can you think of any other applicationCan you think of any other applicationsoftware?software?


19/44

1-1;

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-1;

1.3 How !om"uters Store Data

Concept:

All data that is stored in acomputer is converted tosequences of 0s and 1s.


20/44

1-2<

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-2<


? computer6s memory is i%i e into tiny storage locationsknown as )ytes? :ne !yte represents one num!er ? !yte is i%i e into eight smaller storage locations

known as )its ()inary digits? 'its are tiny electrical components that can hol either a

positi%e or a negati%e charge.? positi%e charge is similar to a switch in the on position

? negati%e charge is similar to a switch in the off position

Figure 1-# 3hink of a !yte aseight switches


21/44

1-21



Storing Numbers? 3he positi%e charge or the on position is represente !y

the igit 1? 3he negati%e charge or the off position is represente !y

the igit <? 3his correspon s to the !inary num!ering system where

all numeric %alues are written as a se@uence of


22/44

1-22


1.3 How !om"uters Store DataStoring Numbers

or e/ample0

Figure 1-11 $etermining the %alueof 1


23/44

1-2#

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-2#


Storing Numbers? 3he largest %alue that can !e store in a !yte with

eight !its is *++ ? 3wo !ytes are use for larger num!ersB ma/imum

%alue is ,++ +

Figure 1-13 3wo !ytes use for a large num!er


24/44

1-2+

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-2+


Storing Characters? &haracters are store in the computer6s memory as

!inary num!er ? AS& (American Standard &ode for nformation

nterchange is a co ing scheme

Figure 1-14 3he letter is store in memory as the num!er 4


25/44

1-2



Storing Characters? S&99 is a set of 127 numeric co es? S&99 is limite

? #nicode is an e/tensi%e enco ing scheme? 9t is compati!le with S&99? 9t represents characters for many languages in the

worl


26/44

1-24



Advanced Number Storage? 'inary num!ering system can !e use to represent

only integer num!ers

? >egati%e num!ers are enco e using two/scomplement

? Aeal num!ers are enco e using floating-pointnotation


27/44

1-25



Other Types of ata? Digital data is ata that is store in !inary? digital device is any e%ice that works with !inary

ata? $igital images are compose of tiny ots of color

known as pixels (picture elements? $igital soun is !roken into small pieces known as

samples


28/44

1-27


1.4 How a %rogram &or s

Concept:

A computer’s CPU can only

understand instructions that arewritten in machine language.

ecause people !nd it verydi"cult to write entire programsin machine language# otherprogramming languages have$een invented.


29/44

1-2;

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-2;


? &P8 is the most important component in a computer ? &P8 is not a !rain

? &P8 is not smart? &P8 is an electronic e%ice that is esigne to o

specific things.


30/44

1-#<

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-#<


&P8 is esigne to perform the following operations0? Aea a piece of ata from main memory? ing two num!ers? Su!tracting one num!er from another num!er ? ultiplying two num!ers? $i%i ing one num!er !y another num!er ? o%ing a piece of ata from one memory location

to another ? $etermining whether one %alue is e@ual to another

%alue


31/44

1-#1

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-#1


? &P8 only un erstan s instructions written in machinelanguage

? achine language instructions are written in 1s an


32/44

1-#2



? "etch-decode-execute cycle is the term use whenthe &P8 e/ecutes the instructions in a program.? 3he cycle consist of three steps0

– etch

– $eco e – =/ecute

Figure 1-1# 3he fetch- eco e-e/ecute cycle


33/44

1-##

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-##

1.4 How a %rogram &or s!rom "achine #anguage to Assemb$y#anguage?&omputers only un erstan machine language? achine language is ifficult to write? Assem)ly language uses short wor s that are known asmnemonics? Assem)ler is use to translate an assem!ly languageprogram to machine language

Figure 1-1' n assem!lertranslates an assem!lylanguage program to amachine language program


34/44

1-#+

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-#+


High%#eve$ #anguages? ssem!ly language is referre to as a low-level language?0igh-level languages allow you to create powerful ancomple/ programs without knowing how the &P8 works,using wor s that are easy to un erstan .

For example: a, ' S9&, Python, &DD, Au!y, Eisual 'asic

Do you know of any other high-Do you know of any other high-level computer programminglevel computer programming

languages?languages?


35/44

1-#

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-#


&ey 'ords( Operators( and Synta): anOverview?1ey words or reserved words ha%e specific meaning anpurpose in the programming language?%perators perform %arious operations on ata?Syntax is a set of rules that must !e strictly followe whenwriting a program?Statements are in i%i ual instructions written in aprogramming language


36/44

1-#4



Compi$ers and *nterpreters?3he statements written in a high-le%el language are calle source code or simply code?Source co e is translate to machine language using a compiler or an interpreter ?Syntax error is a mistake such as a0

? isspelle wor? issing punctuation character ? 9ncorrect use of an operator


37/44

1-#5



Compi$ers and *nterpreters?&ompiler is a program that translates a high-le%ellanguage program into a separate machine languageprogram

Figure 1-1$ &ompiling a high-le%el program an e/ecuting it


38/44

1-#7



Compi$ers and *nterpreters? n interpreter is a program that !oth translates an e/ecutes the instructions in a high-le%el language program

?Python language uses an interpreter

Figure 1-2( =/ecuting a high-le%el program with an interpreter


39/44

1-#;

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-#;

1.) *sing %yt+on

Concept:

The Python interpreter can run

Python programs that are saved in!les# or can interactively e%ecutePython statements that are typedat the &ey$oard. Python comes witha program named '()* thatsimpli!es the process of writing#e%ecuting# and testing programs.


40/44

1-+<

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-+<

1.) *sing %yt+on

The Python *nterpreter ? program that can rea Python programming statementsan e/ecute them is the Python interpreter ?Python interpreter has two mo es0

– nteractive mo e waits for a statement from thekey!oar an e/ecutes it

– Script mo e rea s the contents of a file ( Python program or Python script * an interprets eachstatement in the file


41/44

1-+1

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-+1

1.) *sing %yt+on

*nterpreter "ode?9n%oke Python interpreter through Win ows or comman line?,,, is the prompt that in icates the interpreter is waiting for aPython statement

FFF print ‘Python programming is fun!’Python programming is fun!

FFF

?Statements type in interacti%e mo e are not sa%e as a program

E /E0


42/44

1-+2

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-+2

1.) *sing %yt+on

'riting Python Programs and +unningThem in Script "ode?8se a te/t e itor to create a file containing the Python

statements?Sa%e the file with a .py e/tension?3o run the program0

FFF python test.pyE /E0


43/44

1-+#

Copyright © 2009 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-+#

1.) *sing %yt+on

The * #, Programming ,nvironment?Integrate De%e opment En%ironment ( * #, *

– utomatically installe when Python language isinstalle

– 9t has a !uilt-in te/t e itor – 9$G= e itor colorizes co e

Figure 1-21 9$G=


44/44

Starting out with Python - Chapter 1 PPT

Documents

Transcript of Starting out with Python - Chapter 1 PPT