t 01 b computer intro languages

8/3/2019 t 01 b Computer Intro Languages

1/16

NANKANA SAHIB COLLEGE OF

EDUCATION

Submitted to :

Gaganpreet Kaur

Introduction to Computers- Languages

Submitted By :

Paramjeet KaurRoll No. 97


2/16

Computer OrganizationComputer Organization

A Typical VonA Typical Von--Neumann ArchitectureNeumann Architecture

Example:Example:

1.1. InputInputunitunit2.2. OutputOutputunitunit

3.3. MemoryMemoryunitunit

4.4. Arithmetic and logicArithmetic and logicunit (ALU)unit (ALU)

5.5. Central processingCentral processingunit (CPU)unit (CPU)

6.6. Secondary storageSecondary storage unitunit

Control Circuit

(ex: PC: Program Counter)

ALU

Memor

y

I/O

CPU


3/16

Programming LanguagesProgramming Languages

1.1. Machine languages (machine

Machine languages (machinedependent)dependent)NativeNative tonguetongue of of aa particularparticular kindkind of ofcomputercomputer.. EachEach instructioninstruction isis aa binarybinarystringstring.. TheThe codecode isis usedused toto indicateindicate thetheoperationsoperations toto bebe performedperformed andand thethe

memorymemory cellscells toto bebe addressedaddressed.. ThisThis formform isiseasiesteasiest formform ofof computerscomputers toto understand,understand,butbut isis mostmost difficultdifficult forfor aa personperson totounderstandunderstand..

Strings of numbers giving machine specificStrings of numbers giving machine specificinstructionsinstructions

Example:Example: +1300042774+1300042774

+1400593419+1400593419

+1200274027+1200274027


4/16

Programming LanguagesProgramming Languages (cont.)(cont.)

2.2. Assembly languages (machineAssembly languages (machinedependent)dependent)EnglishEnglish--likelike abbreviationsabbreviations representingrepresentingelementaryelementary computercomputer operationsoperations (translated(translatedviavia assemblers)assemblers)

AgainAgain specificspecific toto onlyonly oneone typetype ofof computercomputer..UsesUses descriptivedescriptive namesnames forfor operationsoperations andanddata,data, ee..gg.. ,, LOADLOAD value,value, ADDADD delta,delta,STORESTORE valuevalue.. AssemblersAssemblers willwill translatetranslatethesethese toto machinemachine languageslanguages.. IntermediateIntermediatelevellevel.. SomewhatSomewhat descriptive,descriptive, butbut basicallybasicallyfollowingfollowing thethe machinemachine instructionsinstructions..

Example:Example: LOAD BASEPAYLOAD BASEPAY

ADD OVERPAY ADD OVERPAY

STORE GROSSPAYSTORE GROSSPAY


5/16

Programming LanguagesProgramming Languages(cont.)(cont.)

3.3. HighHigh--level languageslevel languages (machine(machineindependent)independent)

Codes similar to everyday EnglishCodes similar to everyday English

HighHigh--levellevel languageslanguages:: WriteWrite programprogram instructionsinstructions

calledcalled statementstatement thatthat resembleresemble aa limitedlimited versionversion

ofof EnglishEnglish.. ee..gg..,, thethe statementstatement

valuevalue == valuevalue ++ deltadelta.. PortablePortable,, meaningmeaning itit cancan

bebe usedused onon differentdifferent typestypes ofof computerscomputers withoutwithout

modificationsmodifications.. CompilersCompilers translatetranslate themthem toto

machinemachine languageslanguages.. ExamplesExamples areare FORTRAN,FORTRAN,

PASCAL,PASCAL, COBOL,COBOL, C,C, C++,C++, BASICBASIC etcetc..Use mathematical notations (translated viaUse mathematical notations (translated via

compilers)compilers)

Example:Example:

grossPay = basePay +overTimePaygrossPay = basePay +overTimePay

Example:Example:

Statement: a= a + ba= a + b

10

7

17

7

a

b

a

b

Before

After


6/16

Programming LanguagesProgramming Languages(cont.)(cont.)

Structured programmingStructured programmingDisciplined approach to writing programsDisciplined approach to writing programs

Clear, easy to test and debug and easy to modifyClear, easy to test and debug and easy to modify

MultitaskingMultitasking

Specifying that manySpecifying that many

activities run in parallel (still timesliced)activities run in parallel (still timesliced)

Language Application Area

FORTRAN Scientific programming Formula Translation

COBOL Business data Processing Common Business-Oriented Language

Lisp Artificial Intelligence (AI) List Processing

C System Programming Predecessor B

Prolog AI Logic Programming

Ada Real-time distributed systems Ada Augusta

Byron & Charles Babbage

Smalltalk GUI, OOP Objects talk via messageC++ Supports object & OOP C (++ is the increment

operator)

JAVA SupportsWeb programming Originally named Oak

Origin of Name


7/16

Semantic GapSemantic Gap

A semantic gap exists between theA semantic gap exists between theamount of information conveyed inamount of information conveyed in

assembly language v high levelassembly language v high level

languages. Consider the following Clanguages. Consider the following Csingle statement:single statement:

x = x+3;x = x+3;

This single statement may require manyThis single statement may require many

assembly language statementsassembly language statements

(operations):(operations):

Load memory location24 intoLoad memory location24 intoaccumulatoraccumulator

Add a constant 3 to theAdd a constant 3 to the

accumulatoraccumulator

Store accumulator in memoryStore accumulator in memory

location24location24

The number of executable statementThe number of executable statement

expands greatly during the translationexpands greatly during the translation

process from a high level language intoprocess from a high level language into

assembly language.assembly language.


8/16

C Programming LanguageC Programming LanguageC

HighHigh--level generallevel general--purpose language developed inpurpose language developed in1972 at AT&T Bell Lab. By Dennis Ritchie1972 at AT&T Bell Lab. By Dennis Ritchie from twofrom twoprevious programming BCPL and Bprevious programming BCPL and B

Originally developed to write the UNIX operatingOriginally developed to write the UNIX operating

systemsystem

Hardware independent (portable)Hardware independent (portable)By late 1970's C had evolved to "Traditional C"By late 1970's C had evolved to "Traditional C"

Today, virtually all new operating systems areToday, virtually all new operating systems are

written in C or C++.written in C or C++.

The current standard in C is ANSI C.The current standard in C is ANSI C.

C++ is a more advanced version of C,C++ is a more advanced version of C,incorporating among other things, the objectincorporating among other things, the object--

oriented constructsoriented constructs

StandardizationStandardizationMany slight variations of C existed, and wereMany slight variations of C existed, and were

incompatibleincompatibleCommittee formed to create a "unambiguous, machineCommittee formed to create a "unambiguous, machine--

independent" definitionindependent" definition

Standard created in 1989, updated in 1999Standard created in 1989, updated in 1999

C has become a popular language industry due itsC has become a popular language industry due its

power and flexibilitypower and flexibility


9/16

The C Standard LibraryThe C Standard LibraryC programs consist ofC programs consist ofpieces/modules called functionspieces/modules called functions

A programmer can create his ownA programmer can create his ownfunctionsfunctions

Advantage: the programmer knowsAdvantage: the programmer knowsexactly how it worksexactly how it works

Disadvantage: time consumingDisadvantage: time consuming

Programmers will often use the CProgrammers will often use the Clibrary functionslibrary functions

Use these as building blocksUse these as building blocks

Avoid reAvoid re--inventing the wheelinventing the wheelIf a preIf a pre--made function exists, generallymade function exists, generallybest to use it rather than write your ownbest to use it rather than write your own

Library functions carefully written,Library functions carefully written,efficient, and portableefficient, and portable


10/16

The C Standard LibraryThe C Standard Library(cont.)(cont.)

The Key Software Trend: ObjectsThe Key Software Trend: Objectsin C++ and JAVAin C++ and JAVA

Reusable software components thatReusable software components that

model items in the real worldmodel items in the real world

Meaningful software units: ex:Meaningful software units: ex: Date objects,Date objects,time objects, audio objects, video objects, filetime objects, audio objects, video objects, file

objects, record objectsaobjects, record objectsany noun can beny noun can be

represented as an objectrepresented as an object

More understandable, better organized,More understandable, better organized,and easier to maintain than proceduraland easier to maintain than procedural

programmingprogramming

Favor modularityFavor modularity


11/16

The C Standard LibraryThe C Standard Library

#include #include

main()main()

{{int i;int i;

for (i = 0; i ++; i < 10)for (i = 0; i ++; i < 10)

{{

printf ("Hello World!printf ("Hello World!\\n");n");

}}

}}


12/16

A Typical C Program DevelopmentA Typical C Program Development

EnvironmentEnvironment

1.1. EditEdit

2.Preprocess2.Preprocess

3.3. CompileCompile

4.4. LinkLink

5.5. LoadLoad

6.6. ExecuteExecute

Disk

Disk

Loader

Linker

Compiler

Preprocessor

Editor

Disk

Disk

Disk

Primary Memory

CP

U

Primary Memory

1. Program is created in

the editor and stored on

disk2. Preprocessor

program processes

the code3. Compiler creates object

code and stores it on

disk.

5. Loader puts

program in

memory.

4. Linker links the

object code with

the libraries

6. CPU takes each

instruction and executes

it, possibly storing new

data values as the

program executes

Phases of C Programs:


13/16

A Typical C Program DevelopmentA Typical C Program Development

EnvironmentEnvironment (cont.)(cont.)

Procedure to Prepare a C Program for ExecutionProcedure to Prepare a C Program for Execution

Enter the program code and

save as a source (*.c) file

using Word Processor

(editor)

The linker linksthe new object file

with other object

files

The loader places

the executable file

into memory

Executable

program in

memory

Failure

Success

Source (.c)file on disk

(Format: text)

Revised

source file

New object

(*.obj) files

(Format: binary)

Executable

(*.exe, *.out) file

(Format: binary)Welcome to

CSCI230

Other object

(*.obj) files

Correct

syntaxerrors

List of errors

Compiler attempts totranslate the

program

into machine code

Input

data

Results


14/16

Constructs in C LanguageConstructs in C Language

Type Declarations:Type Declarations: ex:ex: int, float,

I/O:I/O: ex:ex:printf(), scanf()

Arithmetic and LogicalArithmetic and Logical Operations:Operations: ex:ex: +,-,*,/,%,>,


15/16


16/16

Application SoftwareApplication SoftwareDeveloped to assist a computerDeveloped to assist a computer

user in accomplishing specialuser in accomplishing specialtaskstasks

ex: word processing applications:ex: word processing applications:MSMS--word or Wordword or Word--perfectperfect

ex: Spreadsheet applications:ex: Spreadsheet applications:Lotus1Lotus1--22--3, Excel3, Excel

ex: Database: Oracle, MSex: Database: Oracle, MS--AccessAccess

Software Development LifeSoftware Development LifeCycle (SDLC)Cycle (SDLC)

ProblemProblem: specify the problem: specify the problemrequirementsrequirements

AnalysisAnalysis: analyze the problem: analyze the problem

DesignDesign: design the algorithm to: design the algorithm to

solve the problemsolve the problemImplementationImplementation: Implement the: Implement thealgorithmalgorithm

TestingTesting: test and verify the: test and verify thecompleted programcompleted program

MaintenanceMaintenance: maintain and update: maintain and updatethe programthe program

t 01 b computer intro languages

Documents