Introduction to Computer Programmingitc-314

Lecture 04

Basic

• Beginners All-Purposes Symbolic Instructions code, abbreviated as BASIC, was developed at the Dartmouth College, USA, by John Kemeny and Professor Kurtz.

• BASIC languages were initially developed to make it convenient for the people to communicate with computers.

• BASIC has improved over the years , but unfortunately it is not a portable language i.e., a program developed in basic on one computer may not run on another without necessary modifications.

• This is because different versions of BASIC do not conform to the same standards.

• Different versions of Basic Language are: GW-BASIC, Visual Basic, VB.Net etc

FORTRAN• FORTARN (FORmula TRANslation) was developed in 1957 for

IBM 704 computer by a team headed by John Backus.

• A full version of FORTRAN was approved by the American National Standard Institute (ANSI) in 1966.

• FORTRAN was basically developed for scientific and engineering’s data processing purposes.

• FORTRAN has widely been accepted as a language for scientific calculations.

COBOL•Common business Oriented Languages (COBOL) was

specially designed for business purposes.

•COBOL is used all over the world for a variety of data processing tasks, such as payroll, inventory and stock control.

• It is a self documented language and it is convenient to understand a program written in COBOL.

C • C is the high-level language which has the power and many

facilities of low-level languages. • It is used very commonly in system programming and a very

popular operating system UNIX is written in this language. • Its special features are the efficient use of memory and fast

processing speed. • However, it is the choice if many experienced programmers

because the big program of other languages can be written very concisely in C.

PASCAL

•Pascal is named after Blaise Pascal, a French mathematician of the seventeenth century.

•PASCAL language was developed in the late 1960s.

•Pascal was the first major language developed on the concepts of structured programming.

•Pascal can be used for both scientific and business type file processing applications.

Generations of Programming Language

1GL or first-generation language

•1GL or first-generation language was (and still is) machine language.

•Machine languages are the only languages

understood by computers.

•While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers.

•Example: 1011001111111010011101100

2GL or second-generation language

• 2GL or second-generation language is assembly language.

• Its was introduced in 1952 helped in overcoming the limitations of machine language.

• An assembly language contains the same instructions as a machine language, but the instructions and variables have names (Mnemonics) instead of being just numbers.

• For Example: To Add two numbers we write

A 12,8

Assembler

The assembler of a computer system is a system software, supplied by system manufacture, which translates an assembly language program into an equivalent machine language program.

3GL or third-generation language• 3GL or third-generation language is a "high-level"

programming language.

• The first high-level programming languages were designed in the 1950s.

• High level languages are those languages that are closer to human languages and further from machine languages.

• The main advantage of high-level languages over low-level languages is that they are easier to read, write, and maintain.

• Ultimately, programs written in a high-level language must be translated into machine language by a compiler or interpreter.

Compiler & Interpreter

• A compiler is a translator program, which converts the statements of a specific high-level programming language into machine language.

• An interpreter is another type of translator, which is used for translating programs written in high level languages.

• It takes one statement of high level language program, translate it into machine language instructions, and then immediately execute the resulting instructions.

4GL or fourth-generation language

• 4GL or fourth-generation language is designed to be closer to natural language than a 3GL language.

• Fourth generation languages are commonly used in database programming and scripts.

• A 4GL language statement might look like this:

EXTRACT ALL CUSTOMERS WHERE "PREVIOUS PURCHASES" TOTAL MORE THAN $1000

5GL or fifth-generation language

• The fifth generation languages, or 5GL are programming languages that contain visual and graphical tools to help develop a program.

• Fifth-generation languages are used mainly in artificial intelligence research.

• 5GL programs are usually compiled with a 3GL or 4GL language compiler.

•Microsoft, Borland, IBM, and other companies make 5GL visual programming products for developing applications in Java.

• Visual programming allows you to easily envision object-oriented programming class hierarchies and drag icons to assemble program components.