lec 3 - programming language

7/31/2019 Lec 3 - Programming Language

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Soft ware & hardware

Programs,namely, the list of instructions to be executed bya computer are known as the software of a computer

The electronic circuits used in building a computer thatexecutes the soft ware is known as the hardware


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Computer software may be classified in totwo categories

1)System software

2)Application software


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System software

System software is a program thatcontrols the computers hardware orthat can be used to maintain the

computer in some way so that it runsmore efficiently. We have 3 basic typesof system software


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Application software

It tells the computer how to accomplishspecific tasks such as word processing ordrawing for the user. Thousands of

applications are available for manypurposes and for people of all ages. Someof the major categories of theseapplications include

a) Word processing software is used forcreating text based documents such asnews papers or brochures and so on.


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b) spread sheets are designed to usenumbers and formulas to do calculationsvery easily.

commonly used spreadsheet programsare microsoft excel.

c)Database management system(DBMS) is asoftware tool that allows multiple users tostore , access and process data into usefulinformation.

ex: oracle,microsoft access.


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Evo ut on an H storyof Programming

LanguagesSoftware/Hardware/System


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Software

ProgrammingLanguage


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History Timeline


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Machine languages

Assembly languages

Higher-level languages

To build programs, people use languages that are similarto human language. The results are translated into

machine code, which computers understand.

Programming languages fall into three broad categories:

The Evolution of Programming Languages


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Machine languages (first-generation languages) are the

most basic type of computer languages, consisting of

strings of numbers the computer's hardware can use.

Different types of hardware use different machine code.

For example, IBM computers use different machine

language than Apple computers.

The Evolution of Programming Languages -

Machine Languages


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Assembly languages (second-generation languages) are

only somewhat easier to work with than machine

languages.

To create programs in assembly language, developers

use cryptic English-like phrases to represent strings of

numbers.

The code is then translated into object code, using a

translator called an assembler.


Assembly Languages


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Assembler

Assembly

code

Object code


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Third-generation languages

Fourth-generation languages

Fifth-generation languages

Higher-level languages are more powerful than assembly

language and allow the programmer to work in a more

English-like environment.

Higher-level programming languages are divided into three

"generations," each more powerful than the last:


Higher-Level Languages


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FORTAN C

COBOL C++

BASIC Java

Pascal ActiveX

Third-generation languages (3GLs) are the first to

use true English-like phrasing, making them easier to

use than previous languages.

3GLs are portable, meaning the object code createdfor one type of system can be translated for use on a

different type of system.

The following languages are 3GLs:

Higher-Level Languages -

Third-Generation Languages


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A Typical C Program DevelopmentEnvironment

1. Edit

2. Preprocess

3. Compile

4. Link5. Load

6. ExecuteDisk

Disk

Loader

Linker

Compiler

Preprocessor

Editor

Disk

Disk

Disk

Primary Memory

CPU

Primary Memory

1. Program is created in theeditor and stored on disk

2. Preprocessor program

processes the code

3. 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:


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Visual Basic (VB)

VisualAge

Authoring environments

Fourth-generation languages (4GLs) are even easier

to use than 3GLs.

4GLs may use a text-based environment (like a 3GL)

or may allow the programmer to work in a visualenvironment, using graphical tools.

The following languages are 4GLs:


Fourth-Generation Languages


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Fifth-generation languages (5GLs) are an issue of

debate in the programming community some

programmers cannot agree that they even exist.

These high-level languages would use artificial

intelligence to create software, making 5GLs extremely

difficult to develop.

Solve problems using constraints rather thanalgorithms, used in Artificial Intelligence

Prolog


Fifth-Generation Languages


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Summary

lec 3 - programming language

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