Transcript Introduction to Computer Programming itc-314

Introduction to Computer Programming
itc-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, BBC BASIC 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
engineering’s data processing purposes.
and
• 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
understood by computers.
the
only
languages
• 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
programming language.
language
is
a
"high-level"
• 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.
• The branch of computer science concerned with making computers
behave like humans. The term was coined in 1956 by John McCarthy at
the Massachusetts Institute of Technology.
• Artificial intelligence includes
• games playing: programming computers to play games such as chess and
checkers.
• expert systems : programming computers to make decisions in real-life
situations (for example, some expert systems help doctors diagnose
diseases based on symptoms).
• 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.