Download CONCEPTS OF PROGRAMMING LANGUAGES

CONCEPTS OF
PROGRAMMING LANGUAGES
Week 11
Lecture By
Mohamed El Saied
SESSION OBJECTIVE
1.
Introduction To Computer Program or Language
2.
Levels of Computer languages
3.
Language Processors
4.
Generations of Computer Programming
5.
Types of Programming Languages
WHAT IS A PROGRAMMING LANGUAGE?
A set of rules or instrcutions
A set of rules for converting an algorithm
A language framework for describing computations
Symbols, words, rules of grammar, rules of semantics
 Syntax and Semantics
Algorithm
Flowchart
Programs
3
LEVELS OF PROGRAMMING LANGUAGES
High-level Language
class Triangle {
...
float surface()
return b*h/2;
}
Assembly Level
Language
LOAD r1,b
LOAD r2,h
MUL r1,r2
DIV r1,#2
RET
Machine level
Language
0001001001000101001001
001110110010101101001.
..
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LEVELS OF PROGRAMMING LANGUAGESCOND
PROGRAMMING LANGUAGES (CONT’D)
A Machine language program consists of a sequence of zeros and
ones.
Each kind of CPU has its own machine language.
Advantages
Fast and efficient
Machine oriented
No translation required
Disadvantages
Not portable
Not programmer friendly
ASSEMBLY LANGUAGE

Assembly language programs use mnemonics to represent machine
instructions

Each statement in assembly language corresponds to one statement in
machine language.

Assembly language programs have the same advantages and
disadvantages as machine language programs.

Compare the following machine language and assembly language
programs:
8086 Machine language program for
var1 = var1 + var2 ;
8086 Assembly program for
var1 = var1 + var2 ;
1010 0001 0000 0000 0000 0000
0000 0011 0000 0110 0000 0000 0000 0010
1010 0011 0000 0000 0000 0000
MOV AX , var1
ADD AX , var2
MOV var1 , AX
HIGH-LEVEL PROGRAMMING LANGUAGES
 A high-level language (HLL) has two primary components
 (1) a set of built-in language primitives and grammatical rules
 (2) a translator
 A HLL language program consists of English-like statements that are
governed by a strict syntax.
 Advantages
 Portable or machine independent
 Programmer-friendly
 Disadvantages
 Not as efficient as low-level languages
 Need to be translated
 Examples : C, C++, Java, FORTRAN, Visual Basic, and Delphi.
LANGUAGE PROCESSORS
Assembler
Compiler
Interpreter
converting
Assembly to
machine
High level
language to
machine
language
Line by line
compilation
Debugging is
easy
E.g,: TASM
Debugging is
Debugging is
faster
slow
E.g. TC computer Eg: BASIC
BEYOND FIFTH GENERATION LANGUAGES
Some talk about




Agent Oriented Programming
Aspect Oriented Programming
Intentional Programming
Natural language programming
Maybe you will invent the next big language
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GENERATIONS OF PROGRAMMING LANGUAGES
First Generation Languages
Machine
0000 0001 0110 1110
0100 0000 0001 0010
Second Generation Languag es
Assembly
LOAD x
ADD R1 R2
Third Generation Languages
High-level imperative/object oriented
public Token scan ( ) {
while (currentchar == ‘ ’
|| currentchar == ‘\n’)
{….} }
Fortran, Pascal, Ada, C, C++, Java, C#
Fourth Generation Languages
Database
select fname, lname
from employee
where department=‘Sales’
SQL
Fifth Generation Languages
Functional Logic
fact n = if n==0 then 1
else n*(fact n-1)
uncle(X,Y) :- parent(Z,Y), brother(X,Z).
Prolog
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TYPES OF PROGRAMMING LANGUAGES
Procedural Programming Languages
Structured Programming Languages
Object-Oriented Programming Languages
PROGRAMMING LANGUAGES
ASSEMBLY LANGUAGE- FEATURES
In this whole problem is solved as a single block.
This is suitable only for small problem.
Difficult to follow and correct errors
Eg, Assembly Language, BASIC.
PROCEDURE PROGRAMMING
Features of procedure oriented Programming:
Large Programs are divided in to small function or
Procedure.
Uses Top-Down programming Approach.
Data moves freely from one function to another.
Most of the functions share common data.
Emphasis is given for algorithms.
Disadvantages:
Very difficult identify which data is used by which
function.
Error Correction is difficult.
Example: C, Pascal
STRUCTURED PROGRAMMING
1.
The program is divided into
modules and the modules
are then divided into
functions.
2.
Each module can work
independent of one another.
Example: ADA, Prolog
OBJECT ORIENTED PROGRAMMING
1.
The Program is divided into number
of small units called Object. The
data and function are build around
these objects.
2.
The data of the objects can be
accessed only by the functions
associated with that object.
3.
The functions of one object can
access the functions of other object.
Example: C++, Java
OBJECT ORIENTED PROGRAMMING
OBJECT ORIENTED PROGRAMMING
FEATURES OF OBJECT ORIENTED
Features:
Emphasis is given on data rather than procedures.
Problems are divided into objects.
Data structures are designed such that they organize the object.
Data and function are tied together.
POSSIBLE QUESTIONS
What are levels of Programming Languages?
Illustrate difference between Assembler and Compiler
What are features of Procedural Languages
What are features of Structural Languages
What are features of Object oriented Languages
Thank you!
END OF PRESENTATION