meljun cortes - intro. to computers programming language

8/9/2019 MELJUN CORTES - Intro. to Computers Programming Language

1/46

1

IT 209IT 209

Introduction ToIntroduction To

Computers AndComputers AndProgramming LanguageProgramming Language

MELJUN CORTES,MBA,MPAMELJUN CORTES,MBA,MPA


http://meljuncortes.blogspot.com


2/46

MELJUN CORTES,MBA,MPAMELJUN CORTES,MBA,MPAMELJUN CORTES,MBA,MPAMELJUN CORTES,MBA,MPA

LECTURE 1 2

In this chapter, you willIn this chapter, you will::Learn about different types of computersLearn about different types of computers

Explore the hardware and software componentsExplore the hardware and software componentsof a computer systemof a computer system

Learn about the language of a computerLearn about the language of a computer

Learn about the evolution of programmingLearn about the evolution of programming

languageslanguagesExamine high-level programming languagesExamine high-level programming languages

ObjectivesObjectives

MELJUN CORTES MBA MPAMELJUN CORTES MBA MPA


3/46

LECTURE 1 3

Objectives (contObjectives (cont.(.(

Discover what a compiler is and what itDiscover what a compiler is and what it

doesdoes

Examine a C++ programExamine a C++ programExplore how a C++ program is processedExplore how a C++ program is processed

Become aware of Standard C++ andBecome aware of Standard C++ and

ANSI/ISO Standard CANSI/ISO Standard C++++



4/46

LECTURE 1 4

Why ProgramWhy Program??

ComputerComp

uter programmable machine designed to programmable machine designed to

follow instructionsfollow instructions

ProgramProg

ram instructions in computer memory to instructions in computer memory to

make it do somethingmake it do something

ProgrammerProgr

ammer person who writes instructions person who writes instructions

(programs) to make computer perform a task(programs) to make computer perform a task

SO, without programmers, no programs; withoutSO, without programmers, no programs; withoutprograms, a computer cannot do anythingprograms, a computer cannot do anything



5/46

LECTURE 1 5

Categories of ComputersCategories of Computers

Mainframe computersMainframe computers

Midsize computersMidsize computers

Micro computers (personalMicro computers (personal

computerscomputers((



6/46

LECTURE 1 6

Computer is an electronic device, with

two major components.

Computer

Hardware Software

Computer Components



7/46

LECTURE 1 7

Main HardwareMain Hardware

Component CategoriesComponent Categories::

1.1.Central Processing Unit (CPUCentral Processing Unit (CPU((

2.2.Main MemoryMain Memory

3.3.Secondary Memory / StorageSecondary Memory / Storage

4.4.Input DevicesInput Devices

5.5.Output DevicesOutput Devices



8/46

LECTURE 1 8

Main HardwareMain Hardware

Component CategoriesComponent Categories



9/46

LECTURE 1 9

Central Processing UnitCentral Processing Unit

(CPU(CPU((Comprised ofComprised of::

Control UnitControl Unit

Retrieves and decodes program instructionsRetrieves and decodes program instructionsCoordinates activities of all other parts ofCoordinates activities of all other parts of

computercomputer

Arithmetic & Logic UnitArithmetic & Logic Unit

Hardware optimized for high-speed numericHardware optimized for high-speed numericcalculationcalculation

Hardware designed for true/false, yes/noHardware designed for true/false, yes/nodecisionsdecisions



10/46

LECTURE 1 10

CPU OrganizationCPU Organization



11/46

LECTURE 1 11

Main MemoryMain Memory

It is volatile. Main memory is erased whenIt is volatile. Main memory is erased when

program terminates or computer is turned offprogram terminates or computer is turned off

Also called Random Access Memory (RAMAlso called Random Access Memory (RAM((

Organized as followsOrganized as follows::bit: smallest piece of memory. Has values 0 (off,bit: smallest piece of memory. Has values 0 (off,

false) or 1 (on, truefalse) or 1 (on, true((

byte: 8 consecutive bits. Bytes have addressesbyte: 8 consecutive bits. Bytes have addresses..



12/46

LECTURE 1 12

Main MemoryMain Memory

Addresses Each byte in memory isAddresses Each byte in memory is

identified by a unique number knownidentified by a unique number known

as anas an addressaddress..

The number 149 is stored in the byte with the address 16,

and the number 72 is stored at address 23.



13/46

LECTURE 1 13

Main memory with some data

Main Memory



14/46

LECTURE 1 14

Secondary StorageSecondary Storage

Non-volatile: data retained whenNon-volatile: data retained when

program is not running or computerprogram is not running or computer

is turned offis turned offComes in a variety of mediaComes in a variety of media::

magnetic: floppy disk, zip disk, hardmagnetic: floppy disk, zip disk, hard

drivedriveoptical: CD-ROMoptical: CD-ROM

Flash drives, connected to the USB portFlash drives, connected to the USB port



15/46

LECTURE 1 15

Input DevicesInput Devices

Devices that send information to theDevices that send information to the

computer from outsidecomputer from outside

Many devices can provide inputMany devices can provide input::Keyboard, mouse, scanner, digitalKeyboard, mouse, scanner, digital

camera, microphonecamera, microphone

Disk drives and CD-ROM (SecondaryDisk drives and CD-ROM (Secondarystoragestorage((



16/46

LECTURE 1 16

Output DevicesOutput Devices

Output is information sent from aOutput is information sent from a

computer program to the outside worldcomputer program to the outside world..

The output is sent to an output deviceThe output is sent to an output deviceMany devices can be used for outputMany devices can be used for output::

Computer monitor and printerComputer monitor and printer

Floppy, zip disk drives, writable CD drivesFloppy, zip disk drives, writable CD drives

(Secondary storage(Secondary storage((



17/46

LECTURE 1 17

Computer Software

Software: programs that do specific tasks.

Software is divided into 2 categories

Software

System Software Application Software



18/46

LECTURE 1 18

System Software

Related software that manages the systems resources

and control the operations of the hardware.

Normally supplied by the manufacturer of the computer.

Consists of utility programs and operating aids thatfacilitate the use and performance of the computer.

System programs take control of the computer, such as

an operating system.

Operating system are programs that manage the

computer hardware and the programs that run on them.

Examples: Windows, UNIX, Linux.



19/46

LECTURE 1 19

Application Software

Programs that provide services to the user. Designed to perform a specific task such as

course registration or banking( OR a general-purpose task such as word processing, eg. Ms

Word(. May be acquired by purchasing off-the-shelf or

by designing for own purpose custome made(.

Off-the-shelf : prewritten and ready to use.

Custom made : written by in-house, consulting

firm or software house.



20/46


21/46

LECTURE 1 21

Computing Environment

Personal Computing

Time-Sharing

Client / Server

Computing

Internet Computing



22/46

LECTURE 1 22

Personal computing environment



23/46

LECTURE 1 23

Time-sharing environment



24/46

LECTURE 1 24

The client/server environment



25/46

LECTURE 1 25

Digital signals are sequences of 0s and 1sDigital signals are sequences of 0s and 1sMachine languageMachine language: language of a computer: language of a computer

Binary digit (bitBinary digit (bit

((

::

The digit 0 or 1The digit 0 or 1

Binary codeBinary code::A sequence of 0s and 1sA sequence of 0s and 1s

ByteByte

::

A sequence of eight bitsA sequence of eight bits

The Language of aThe Language of a

ComputerComputer



26/46

LECTURE 1 26



27/46

LECTURE 1 27

Coding SchemesCoding Schemes

ASCII (American Standard Code forASCII (American Standard Code for

Information InterchangeInformation Interchange((128128characterscharactersA is encoded as 1000001 (66thA is encoded as 1000001 (66th

charactercharacter((

33is encoded as 0110011is encoded as 0110011



28/46


29/46

LECTURE 1 29

History Of Computer Languages

Computer language evolution

The only language understood by a computer is

machine language



30/46

LECTURE 1 30

1.Machine Language

Computer only understand this language.

Series of 1s and 0s binary numbers(, such as

1011010000000101

Difficult to write.

Low level language


cont.(



31/46

LECTURE 1 31

Early computers were programmed inEarly computers were programmed in

machine languagemachine language

To calculateTo calculate wages = rates * hourswages = rates * hours ininmachine languagemachine language::

100100100100010001010001////LoadLoad

100110100110010010010010////MultiplyMultiply100010100010010011010011////StoreStore

History Of ComputerHistory Of Computer

Languages (contLanguages (cont.(.(



32/46

LECTURE 1 32

22..Symbolic/Assembly LanguageSymbolic/Assembly LanguageUnique to particular computerUnique to particular computer..

Use mnemonics symbols. E.g. MUL MultiplyUse mnemonics symbols. E.g. MUL Multiply

Easier to understandEasier to understand..





33/46

LECTURE 1 33

Using assembly language instructions,Using assembly language instructions,

wages = rates hourswages = rates hours

can be written ascan be written as::LOAD rateLOAD rate

MULTMULThourhour

STORSTORwageswages





34/46

LECTURE 1 34

33..High-Level LanguageHigh-Level LanguagePortable to many different computersPortable to many different computers..Instruction are codedInstruction are coded

Eg. COBOL (Business), FORTRAN (Scientific), BASIC,Eg. COBOL (Business), FORTRAN (Scientific), BASIC,Pascal, C, C++, C#, Java etcPascal, C, C++, C#, Java etc..

Programmers use this to write programsProgrammers use this to write programs..CompilerCompiler: translates a program written in a high-level: translates a program written in a high-level

language machine languagelanguage machine language

The equationThe equation wages = rate x hourswages = rate x hours can be written in C+can be written in C++ as+ as::

wages = rate * hourswages = rate * hours;;





35/46

LECTURE 1 35

4. Natural Language

Like our natural language such as English,French, or Chinese(

Its use is still quite limited.


cont.(



36/46

S W ll K Hi hS W ll K Hi h


37/46

LECTURE 1 37

Some Well-Known High-Some Well-Known High-

Level ProgrammingLevel Programming

LanguagesLanguages



38/46

LECTURE 1 38

##include


39/46

LECTURE 1 39

Program Development

A computer understands a program only ifthe program is coded in its machine

language.

Programmer have to write the program

and turn it into an executable machine

language( code.

Programmer have to understand the

problem -< break into actions-< execute bythe computer.





40/46

LECTURE 1 40

From a High-level ProgramFrom a High-level Program

to an Executable Codeto an Executable CodeThere are 4 steps in the processThere are 4 steps in the process::

a)a)Create and edit file containing the program with a text editorCreate and edit file containing the program with a text editor..

b)b)RunRun preprocessorpreprocessor to process the preprocessor directives (begin withto process the preprocessor directives (begin with#(#(

c)c)RunRun compilercompiler toto::

Check that the program obeys the rulesCheck that the program obeys the rulesTranslate into machine language (object codeTranslate into machine language (object code((

d)d)RunRun linkerlinker to connect hardware-specific code to machine instructions,to connect hardware-specific code to machine instructions,producing an executable codeproducing an executable code..

Steps bd are often performed by a single command or button clickSteps bd are often performed by a single command or button click..Errors detected at any step will prevent execution of following stepsErrors detected at any step will prevent execution of following steps..

, ,, ,


41/46

LECTURE 1 41Executable Code

Code

Code

Programmer

From a High-level Program to an Executable Code



42/46

LECTURE 1 42

LoaderLoader::Loads executable code/program intoLoads executable code/program into

main memorymain memoryExecutionExecution::

The last step is to execute the programThe last step is to execute the program

Program DevelopmentProgram Development

(cont(cont.(.(



43/46


44/46

LECTURE 1 44

Integrated DevelopmentIntegrated Development

Environments (IDEsEnvironments (IDEs((An integrated development environment,An integrated development environment,

or IDE, combine all the tools needed toor IDE, combine all the tools needed towrite, compile, and debug a program intowrite, compile, and debug a program into

a single software applicationa single software application..

Examples are Microsoft Visual C++,Examples are Microsoft Visual C++,

Borland C++ Builder, CodeWarrior, etcBorland C++ Builder, CodeWarrior, etc..



45/46

LECTURE 1 45

Integrated DevelopmentIntegrated Development

Environments (IDEsEnvironments (IDEs((



46/46

meljun cortes - intro. to computers programming language

Documents