Types of Computer Types of Computer Languages Languages 24 July 2007 24 July 2007 Syarilla Iryani Syarilla Iryani Ahmad Ahmad Saany Saany GS GS 19011 19011 Teh Phoey Teh Phoey Lee Lee GS18487 GS18487 Mohd Yunus Mohd Yunus bin bin Sharum Sharum GS19143 GS19143 Sajilal Divakaran Sajilal Divakaran GS18625 GS18625 Mohd Zali Mohd Zali GS18971 Koh Tieng Wei Koh Tieng Wei GS18788 GS18788 Hyder Natiq Hyder Natiq GS????? GS????? SAK6200 ADVANCED PROGRAMMING LANGUAGES
• Because programs are not written in 1s and 0s, the computer must first translate
the program before it can be executed.
Assembly Language– 2nd generation language
– Replaced binary digits with mnemonics (e.g., “ADD”) programmers could more easily
understand
Machine Languages
– 1st generation programming language
– Considered a low-level language because it involves basic coding using
the binary symbols 1 and 0
Generation of Programming Languages
First Generation LanguagesMachine
0000 0001 0110 1110
0100 0000 0001 0010
Second Generation LanguagesAssembly
LOAD x
ADD R1 R2
Third Generation LanguagesHigh-level imperative/object oriented
public Token scan ( ) {
while (currentchar == ‘ ’
|| currentchar == ‘\n’)
{….} }
Fourth Generation LanguagesDatabase
select fname, lname
from employee
where department=‘Sales’
Fifth Generation LanguagesFunctional Logic
fact n = if n==0 then 1 uncle(X,Y) :- parent(Z,Y), brother(X,Z).
else n*(fact n-1)
Fortran, Pascal, Ada, C, C++, Java, C#
SQL
Lisp, SML, Haskel, Prolog
Programming Language Genealogy
Need for High Level Languages
• Limitations of Low Level Languages
– difficult to program in
• machine oriented: instructions are based on what the
processor can do.
– programs will run on one processor only.
• Advantages of High Level Languages
– easier to program in
• more like English
• problem oriented: instructions are based on the type of
things the programmer wishes to do.
– programs may run on different machines.
Features of High Level Languages
• Extensive vocabulary of ‘key’ words, symbols and
sentences.
• A single instruction is very powerful and may be
translated into many machine language
instructions.
• Libraries of subroutines available.
• You must obey the syntax of the language (the
rules).
Language Categories
Programming Languages can be categorised in
many different ways. Some of the categorise are as
follows:
• Procedural Languages
• Nonprocedural Languages
• Imperative Languages
• Declarative Languages
• Functional Languages
• Logic Languages
• Objected Oriented Languages
• Fourth Generation
• Fifth Generation
• Scripting Languages
Please notes some these categories overlap, and some languages
belong to more than one category
Language Categories
• Imperative Languages
– A language which operates by a sequence of commands that change the value of data elements.
– Central features are variables, assignment statements, and iteration
– Language control structures direct the computer to execute an exact sequence of statements.
– Examples: C, Pascal, Fortran, Basic, C
• Functional Languages
– A functional language is one that operates by use of higher-order functions, building that manipulate functions directly without ever appearing to manipulate data.
– Main means of making computations is by applying functions to given parameters
– Examples: LISP, Scheme. Miranda, ML, Hope and HQL
• Logic Languages
– A logic language deals with predicates or relationships p(X,Y).
– Rule-based (rules are specified in no particular order)
– It allows a programmer to describe the logical structure of a problem rather than prescribe how a computer is to go about solving it.
– Example: Prolog, SASL, LOGLIST, FUNLOG
Language Categories
Procedural programming language
• A Procedural programming language provides the means for a programmer to precisely each step in performance of task.
• Through the language, step-by-step instructions on how the task is to be done
• The programmer specifies language statements to perform a sequence of algorithmic steps.
• In a nonprocedural language the programmer tells the computer, through the language, what must be done, but leaves the details of how to perform the task to the language itself.
• For examples: Dbase, ADS, SQL
• Note that fourth-generation languages are all considered nonprocedural.
Visual Programming Languages (GUI)
• Languages that use a mouse, icons, or symbols on the screen and pull-down menus to develop programs
• Examples: Visual C++, Visual Basic
Language Categories
• Markup
– New; not a programming per se, but used to specify the layout of information in Web documents
– Scripting languages (commonly called scripting programming languages or script languages) are computer programming languages that are typically interpreted and can be typed directly from a keyboard. Thus, scripts are often distinguished from programs, because programs are converted permanently into binary executable files (i.e., zeros and ones) before they are run.
– Examples: XHTML, XML Language Categories
• Object-oriented Languages
– Languages that allow interaction of programming objects, including data elements and the actions that will be performed on them
– It define uses classes, inheritance and polymorphism
LISP (List processing and artificial intelligence)
Program Domains
• Multipurpose
– useful over a variety of application areas eg. BASIC (easy to learn and use), C (more difficult but more standard and powerful)
• Applications Generators
– 4th generation languages used to generate programs. Generally used for very specific range of tasks eg generating input forms.
• Operating system command languages
– most operating systems respond to commands and can also read files that contain a sequence of OS commands. The OS may also have the ability to store things in variable and to call other command files (and even to pass parameters to these files).
References
• Software Engineering Fundamentals, Ali Behforooz and Frederick J.
