Introduction To Computer Programming

Instructor : HUSSAIN IBRAHIM
Govt: College of Technology Hyderabad.
Email: amur.hb@gmail.com
INTRODUCTION TO COMUTER PROGRAMMING
(COMP-112)

 What is a programming language?
Why are there so many programming languages?
What are the types of programming languages?
Does the world need new languages?
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A programming language is a set of rules that
provides a way of telling a computer what
operations to perform.
A programming language is a set of rules for
communicating an algorithm
It provides a linguistic framework for
describing computations
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A programming language is a notational system for
describing computation in a machine-readable and
human-readable form.
A programming language is a tool for developing
executable models for a class of problem domains.
PS — Introduction
A programming language is a tool for developing
executable models for a class of problem domains.
A programming language is a notational system for
describing computation in a machine-readable and
human-readable form.

English is a natural language. It has words,
symbols and grammatical rules.
A programming language also has words,
symbols and rules of grammar.
The grammatical rules are called syntax.
Each programming language has a different
of syntax rules.
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 set

Why does some people speak French?
Programming languages have evolved over time as
better ways have been developed to design them.
◦ First programming languages were developed in the
1950s
◦ Since then thousands of languages have been developed
Different programming languages are designed for
different types of programs.
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class Triangle {
...
float surface()
return b*h/2;
}
LOAD r1,b
LOAD r2,h
MUL r1,r2
DIV r1,#2
RET
0001001001000101
0010010011101100
10101101001...
High-level program
Low-level program
Executable Machine code 0001001001000101
0010010011101100
10101101001...
LOAD r1,b
LOAD r2,h
MUL r1,r2
DIV r1,#2
RET
class Triangle {
...
float surface()
return b*h/2;
}

First Generation Languages
Second Generation Languages
Third Generation Languages
Fourth Generation Languages
Fifth Generation Languages
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Machine language
◦
◦
◦
Operation code – such as addition or subtraction.
Operands – that identify the data to be processed.
Machine language is machine dependent as it is the
only language the computer can understand.
Very efficient code but very difficult to write.◦

Assembly languages
◦ Symbolic operation codes replaced binary operation
codes.
Assembly language programs needed to be “assembled”◦
for execution by the computer. Each assembly language
instruction is translated into one machine language
instruction.
Very efficient code and easier to write.◦

Closer to English but included simple
mathematical notation.

◦ Programs written in source code which must be
translated into machine language programs called object
code.
The translation of source code to object code is
accomplished by a machine language system program
called a compiler.
◦

Alternative to compilation is interpretation which is
accomplished by a system program called
interpreter.
an
Common third generation languages
◦
◦
◦
◦
FORTRAN
COBOL
C and C++
Visual Basic

A high level language (4GL) that requires fewer
instructions to accomplish
generation language.
Used with databases
a task than a third

◦
◦
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◦
Query languages
Report generators
Forms designers
Application generators

Declarative languages
Functional(?): Lisp, Scheme,
◦ Also called applicative
◦ Everything is a function

SML
Logic: Prolog
◦ Based on mathematical logic
◦ Rule- or Constraint-based

Though no clear definition at present, natural
language programs generally can be interpreted
and executed by the computer with no other
action by the user than stating their question.
Limited capabilities at present.
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Imperative Programming (C)
Object-Oriented Programming (C++)
Logic/Declarative Programming (Prolog)
Functional/Applicative Programming (Lisp)
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Two broad groups
◦ Traditional programming languages
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
Sequences of instructions
First, second and some third generation languages
◦ Object-oriented languages
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Objects are created rather than sequences of instructions
Some third generation, and fourth and fifth generation
languages

FORTRAN
◦
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FORmula TRANslation.
Developed at IBM in the mid-1950s.
Designed for scientific and mathematical applications by
scientists and engineers.

COBOL
◦
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COmmon Business Oriented Language.
Developed in 1959.
Designed to be common to many different computers.
Typically used for business applications.

BASIC
◦
◦
◦
Beginner’s
Developed
Developed
All-purpose Symbolic Instruction Code.
at Dartmouth College in mid 1960s.
as a simple language for students to write
programs with which they could interact through
terminals.

C
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
Developed by Bell Laboratories in the early 1970s.
Provides control and efficiency of assembly language
while having third generation language features.
Often used for system programs.
UNIX is written in C.
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Simula
◦ First object-oriented language
◦ Developed by Ole Johan Dahl in the 1960s.
Smalltalk
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First purely object-oriented language.
Developed by Xerox in mid-1970s.
Still in use on some computers.

C++
◦
◦
It is C language with additional features.
Widely used for developing system and application
software.
Graphical user interfaces can be developed easily with
visual programming tools.
◦

JAVA
◦ An object-oriented language similar to C++ that
eliminates lots of C++’s problematic features
Allows a web page developer to create programs for
applications, called applets that can be used through a
browser.
Objective of JAVA developers is that it be machine,
platform and operating system independent.
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Scripting Languages
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JavaScript and VBScript
Php and ASP
Perl and Python
Command Languages
◦ sh, csh, bash
Text processing Languages
◦ LaTex, PostScript
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HTML
◦
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HyperText Markup Language.
Used on the Internet and the World Wide Web (WWW).
Web page developer puts brief codes called tags in the
page to indicate how the page should be formatted.

XML
◦ Extensible Markup Language.
◦ A language for defining other languages.
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Programming languages are languages
When it comes to mechanics of the task,
learning to speak and use a programming
language is in many ways like learning to speak
a human language
In both kind of languages you have to learn new
vocabulary, syntax and semantics (new words,
sentence structure and meaning)
And both kind of language require considerable
practice to make perfect.
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Computer languages
vagueness
In English sentences
lack ambiguity and
such as I saw the man with a
telescope (Who had the telescope?) or Take a
pinch of salt (How much is a pinch?)
In a programming language a sentence either
means one thing or it means nothing


Formerly: Run-time performance
◦ (Computers were more expensive than programmers)
Now: Life cycle (human) cost is more important
◦
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Ease of designing,
Debugging
Maintenance
Reusability
coding
FADS

Writability: The quality of a language that enables a
programmer to use it to express a computation clearly,
correctly, concisely, and quickly.
Readability: The quality of a language that enables a
programmer to understand and comprehend the nature of a
computation easily and accurately.
Reliability: The quality of a language that assures a program
will not behave in unexpected or disastrous ways during
execution.
Maintainability: The quality of a language that eases errors
can be found and corrected and new features added.
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ProgrammingCycleSteps
1. TrytounderstandandanalyzetheProblem.
2. Writethealgorithmordrawtheflowchartfortheproblem
3. CreateTheSourcefileusingeditorandthecodeaccordingtothe
flowchartoralgorithm.
4. CompileTheprogramusingsystemsoftwareandtheobjectfileis
created.
5. Step4isrepeatdtillthesourceprogramcontainsnocompilation
errorsthanstep6.
6. Linkthenecessarylibraryfilesneededforthecompilationerrors.
7. Loadthefileforexecution.
8. Executetheprogramusingtherunoption.

Flowchart
 A flowchart is a type of diagram that
represents a workflow or process. A flowchart
can also be defined as a diagrammatic
representation of an algorithm, a step-by-step
approach to solving a task.
 The flowchart shows the steps as boxes of
various kinds, and their order by connecting
the boxes with arrows.
 Flowcharts are used in analyzing, designing,
documenting or managing a process or
program in various fields.

Common symbols
Rectangle Shape - Represents a process
Oval or Pill Shape - Represents the start
or end
Diamond Shape - Represents a decision
Parallelogram - Represents input/output

Terms
HARDWARE – Computer hardware includes
the physical, tangible parts or components of
a computer, such as the cabinet, central processing
unit, monitor, keyboard, computer data
storage, graphics card, sound
card, speakers and motherboard
software, is a collection of data or computer instructions
that tell the computer how to work.

Peopleware is a term used to refer to one of the three core
aspects of computer technology, the other two being hardware
and software .
Peopleware can refer to anything that has to do with the role of
people in the development or use of computer software and
hardware systems, including such issues as developer
productivity, teamwork, group dynamics, the psychology of
programming, project management, organizational factors,
human interface design, and human-machine-interaction.
Peopleware

Introduction To Computer Programming

Introduction To Computer Programming

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