Grey - Pascal programming: Getting Started with Pascal

Pascal programming: Getting Started with Pascal.

Dean Grey

Chapte r A n Overview

Thi s chapte r provide s a n introductio n t o th e Programmin g Practice : Pascal , an overvie w o f curren t computin g device s an d systems , an d a brie f introductio n of Pasca l an d programming . Bein g a n overview , thi s chapte r cover s a wid e rang e of subjects , an d details . D o no t b e overwhelmed ! Man y o f th e topic s wil l be discusse d i n mor e detai l i n othe r chapters . Thi s chapte r ca n b e rea d quickly.

Chapte r Overview

1.1 Preview....................................................................14

1.2 Introductio n t o Programmin g Practice : Pascal.............15

A Globa l View..........................................................15

Th e Roa d Ahead.......................................................15

Sign s Alon g th e Road................................................16

1.3 Hardware : Computer s an d Peripherals.....................17

Th e CPU...................................................................18

Othe r Component s an d Packaging..............................19

1.4 Th e Worl d o f Programming........................................20

Wha t i s Programming?..............................................20

Rea l world an d Abstrac t World..........................20

1.5 Pascal.......................................................................21

A n exampl e Pasca l program.......................................22

Running Programs: Compiling, Linking, Executing......23

1.6 Communicatin g t o Computers.....................................24

Typing......................................................................24

1.7 Chapte r Review.....................................................27

Preview

This book intends to teach you how to program a computer using the Pascal programmin g language , usin g th e concept s an d topic s discusse d i n th e Principles o f Programming.

Althoug h th e journe y throug h th e Principle s o f Programmin g i s echoed throughou t thi s book , thei r ar e som e additiona l obstacle s an d terrai n tha t must b e deal t wit h whe n learnin g th e Pasca l programmin g language . Thi s chapter provide s yo u wit h a guid e t o thes e obstacle s an d outline s th e ne w terrai n by introducin g th e Programmin g Practice : Pasca l i n thre e subsections:

A Globa l Vie w describe s th e layou t o f th e tex t book s materia l i n very genera l detail . Thi s sub-sectio n als o offer s a n ide a o f th e wa y i n which th e Programmin g Practice : Pasca l shoul d b e use d wit h it s companion book: the Principles of Programming.

Th e Roa d Ahea d give s a ver y brie f synopsi s o f eac h chapte r s o tha t you ca n visualiz e ho w al l th e chapter s fi t together . Thi s provide s a route tha t wil l tak e yo u fro m a n introductio n t o computers , programs , an d the compilin g proces s (th e las t sectio n i n thi s chapter ) t o bein g abl e t o write larg e usefu l program s i n Pascal.

Roa d Sign s describe s th e commo n patter n o n whic h eac h o f th e chapters ar e based , tell s yo u ho w t o rea d th e roa d signs , an d give s a brief explanatio n o f som e o f th e visua l aid s tha t wil l b e use d throughou t this book.

Apar t fro m introducin g th e Programmin g Practice : Pascal , thi s chapte r also introduce s th e physica l device s fro m whic h th e compute r syste m i s constituted. The hardwar e as its commonly referred to is the part of the computer system tha t change s mos t rapidly . A s ne w technolog y i s developed , becomin g faster, cheape r an d smaller , i t replace s th e old . Fo r thi s reason , w e wil l concentrat e on th e smalle r micro-computer s an d mini-computers , whic h ar e mor e powerfu l than th e monster computer s o f jus t a fe w year s ago.

Programmin g i s th e creativ e proces s o f designin g an d realizin g software. Programs are written using programming languages of which there are many. In thi s book , w e emphasiz e th e high-leve l programmin g languag e calle d Pascal, bu t mos t o f th e concept s we'l l introduc e als o appl y t o othe r languages.

Communication between people and computers at a detailed level is often done usin g a keyboard . Thi s chapte r include s a brie f discussio n o f th e practica l skill of touch typing, which is useful for anyone wishing to communicate with computers . A sampl e progra m whic h teache s typin g i s show n i n Chapte r

I n summary , thi s chapte r provide s a n introductio n t o th e man y practica l aspects o f computin g today , an d i t doe s s o b y concentratin g o n som e typica l aspects . It emphasizes micro-computers over larger computers, but most of the material describe d applie s equall y t o al l computers . I t aim s t o introduc e yo u t o the practice of programming.

Introductio n t o Programmin g Practice : Pascal

A Globa l View

The goal of this book is to teach you how to program computers using the Pascal programmin g language . However , learnin g t o writ e compute r program s i s very muc h lik e learnin g an y skill , yo u mus t firs t understan d th e underlyin g principles upo n whic h th e craf t i s base d an d the n practice , practice , practice.

Fo r example , yo u ca n rea d al l th e book s eve r publishe d abou t ridin g a bicycl e but, unti l yo u actuall y ge t o n on e an d star t pedalin g o n you r own , yo u wil l no t know ho w t o rid e a bicycle . Th e sam e applie s t o compute r programming ! Here , we provid e th e secon d book , th e Programmin g Practice : Pascal , whic h assume s that yo u hav e alread y familiarize d yoursel f wit h th e Principle s o f Programming (referre d t o a s Principles) : th e firs t boo k whic h describe s th e metho d behind proble m solvin g usin g a computer.

A s i n th e Principle s book , Programmin g Practice : Pasca l emphasize s th e adage, it s bes t t o lear n throug h examples. Eac h chapte r use s exampl e programs, man y take n fro m th e Principle s book , t o teac h th e sam e point . Fo r thi s reason, you may find the number of examples overwhelming and you should feel free to pa y attentio n t o onl y th e example s whic h yo u fee l bes t describ e th e poin t tha t is bein g illustrated.

Th e Roa d Ahead

I n thi s section , w e giv e a brie f summar y o f wha t i s i n eac h chapte r o f the Programmin g Practice : Pascal . A synopsi s o f eac h chapte r i s presente d s o that yo u ca n visualiz e th e roa d ahead.

Chapte r , Computing : A shor t surve y o f som e applications , thi s chapter introduce s softwar e b y givin g som e example s o f package d programs, applications , whic h perfor m specifi c tasks.

Chapte r , Programmin g Language : Pascal , i n thi s chapte r w e further introduce the Pascal programming language by comparing it to natural language s an d b y usin g synta x diagram s t o hel p ou r understanding . Some extremel y simpl e Pasca l progra m example s ar e give n a s illustration s of th e synta x presented . Althoug h i t wil l tak e a fe w mor e chapter s to introduc e al l o f th e Pasca l syntax , som e othe r example s o f complete Pasca l program s ar e als o give n i n thi s chapter.

Chapte r , Dat a an d Actions , thi s chapte r continue s wit h the introductio n t o th e Pasca l programmin g languag e tha t wa s starte d i n the last two chapters. Its main concerns are the basic components of the languag e wit h som e emphasi s o n th e wa y i n whic h th e languag e is

writte n (i.e . th e synta x o r grammar ) bu t als o o n th e precis e meanin g (i.e. th e semantics ) o f wha t i s written.

Chapte r , Th e Fou r Fundamenta l Form s i n Pascal , th e goa l o f this chapte r i s t o introduc e th e fou r fundamenta l forms : Sequence , Selection, Repetition , an d Invocation , tha t ar e necessar y an d sufficien t t o create an y algorithm . A t th e en d o f th e chapte r yo u wil l hav e th e necessary tool s t o develo p you r ow n programs.