Lecture 5 6 introduction to computer programming
This presentation is the property of its rightful owner.
Sponsored Links
1 / 66

Lecture 5+6 Introduction to computer & programming PowerPoint PPT Presentation


  • 76 Views
  • Uploaded on
  • Presentation posted in: General

Lecture 5+6 Introduction to computer & programming. MS SADIA EJAZ CS DEPARTMENT. The Internet. It is a huge network of computers, which links many different types of computers all over the world.

Download Presentation

Lecture 5+6 Introduction to computer & programming

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Lecture 5 6 introduction to computer programming

Lecture 5+6Introduction to computer & programming

MS SADIA EJAZ

CS DEPARTMENT

MS Sadia Ejaz CIIT ATTOCK


The internet

The Internet

It is a huge network of computers, which links many different types of computers all over the world.

It is a network of networks, which share a common mechanism for addressing (identifying) computers, and a common set of communication protocols for communication between two computers on the network.

MS Sadia Ejaz CIIT ATTOCK

2


The internet s major services

The Internet’s Major Services

The World Wide Web

Electronic mail

News

File Transfer Protocol

Chat

Instant Messaging

Online- Services

Peer-to-Peer Services

MS Sadia Ejaz CIIT ATTOCK

3


The world wide web

The World Wide Web

The World Wide Web (commonly shortened to the Web) is a system of interlinked hypertext documents accessed via the Internet.

With a Web browser, a user views Web pages that may contain text, images, videos, and other multimedia and navigates between them using hyperlinks.

MS Sadia Ejaz CIIT ATTOCK

4


Web search engine

Web Search Engine

A Web search engine is a search engine designed to search for information on the World Wide Web.

A search engine lets you search for information by typing one or more words. The engine then displays a list of Web pages that contain information related to your words.

Example: Google search engine

MS Sadia Ejaz CIIT ATTOCK

5


E mail

E - Mail

Electronic mail, often abbreviated to e-mail, is a store-and-forward method of writing, sending, receiving and saving messages over electronic communication systems.

6


Programming language generations

Programming Language Generations

  • Machine languages: first generation

  • Assembly languages: second generation

  • Higher-level languages: third generation (3GLs)

MS Sadia Ejaz CIIT ATTOCK


Fading third generation languages

Fading Third-Generation Languages

  • FORTRAN (FORmula TRANslator)

  • COBOL (COmmon Business Oriented Language)

  • BASIC (Beginner’s All-Purpose Symbolic Instruction Code)

  • Pascal

MS Sadia Ejaz CIIT ATTOCK


Thriving third generation languages

Thriving Third-Generation Languages

  • C

  • C++

  • Java

  • ActiveX

MS Sadia Ejaz CIIT ATTOCK


Fourth generation languages 4gls

Fourth-Generation Languages (4GLs)

  • Builds programs with a front end, which is an interface that hides much of the program from the user

  • Provides prototypes, which are samples of the finished programs

MS Sadia Ejaz CIIT ATTOCK


Examples of fourth generation languages

Examples of Fourth-Generation Languages

  • Visual Basic (VB)

  • VisualAge

  • Authoring environments

MS Sadia Ejaz CIIT ATTOCK


Fifth generation languages 5gls

Fifth-Generation Languages (5GLs)

  • Advanced authoring environments considered by some to be 5GLs

MS Sadia Ejaz CIIT ATTOCK


World wide web development languages

World Wide Web Development Languages

  • HyperText Markup Language (HTML)

  • Extensible Markup Language (XML)

  • Wireless Markup Language (WML)

  • Dreamweaver

  • Flash

  • Director

MS Sadia Ejaz CIIT ATTOCK


Systems development life cycle for programming

Systems Development Life Cycle for Programming

  • Phase 1: Needs analysis

  • Phase 2: Program design

  • Phase 3: Development (also called coding)

  • Phase 4: Implementation

  • Phase 5: Maintenance

MS Sadia Ejaz CIIT ATTOCK


Why we do programming

Why We Do Programming ?

  • For solving problems

    • Computers are used as a tool to solve complex problems by developing computer programs that provide the solution of the problems.

    • Example:

      • Program : For adding 2 numbers, i.e 3 and 5

      • Solution: A computer program will be developed for their addition.

MS Sadia Ejaz CIIT ATTOCK


Problem solving techniques

Problem-Solving Techniques

  • Program

  • Algorithm

  • Pseudo Code

  • Flowchart , etc.

MS Sadia Ejaz CIIT ATTOCK


Program

Program

  • A set of instructions that tells a computer what to do is called program.

  • Computer programs are written in programming languages.

  • A person who develops a program is called programmer.

MS Sadia Ejaz CIIT ATTOCK


Algorithms

Algorithms

  • It is a step-by-step procedure to solve a problem.

  • Properties of Algorithm

    • The given problem should be broken down into simple and meaningful steps.

    • The steps should be numbered sequentially.

    • The steps should be descriptive and written in simple English.

MS Sadia Ejaz CIIT ATTOCK


Pseudo code pseudo language

Pseudo Code / Pseudo Language

  • Algorithms are written in a language, which is similar to simple English , which is known as pseudo language.

  • The purpose of using pseudo code is that it may be easier for humans to read than conventional programming languages.

  • No standard for pseudo code syntax exists, as a program in pseudo code is not an executable program.

MS Sadia Ejaz CIIT ATTOCK


Parts of program development

Parts of Program Development

  • Two main parts

    • Logic Design

    • Coding

MS Sadia Ejaz CIIT ATTOCK


Logic design

Logic Design

  • Logic of the program is designed by specifying different steps required and the sequence of these steps to solve the problem.

MS Sadia Ejaz CIIT ATTOCK


Coding

Coding

  • The algorithm is converted into a program.

MS Sadia Ejaz CIIT ATTOCK


Example

Example

  • Algorithm for calculating and displaying the sum of two numbers,

    • Input A, B

    • Total / Sum A + B

    • Display Total

    • Exit

MS Sadia Ejaz CIIT ATTOCK


Advantages of algorithms

Advantages of Algorithms

  • Reduced Complexity

  • Increased Flexibility

  • Ease of Understanding

MS Sadia Ejaz CIIT ATTOCK


Flowchart

Flowchart

  • It is combination of two words i.e. flow and chart.

  • Flowchart is a graphical representation of an algorithm.

    • Chart consists of different symbols to display information about any program.

    • Flow indicates the direction of processing that takes place in the program.

  • It is used to show all the steps of an algorithm in a sequence.

MS Sadia Ejaz CIIT ATTOCK


Flowchart contd

Flowchart (contd.)

MS Sadia Ejaz CIIT ATTOCK


Uses of logic flowchart

Uses of Logic Flowchart

  • It is used to represent an algorithm in simple graphical manner.

  • It is used to show the steps of an algorithm in an easy way.

  • It is used to understand the flow of the program.

  • It is used to improve the logic for solving a problem.

  • Programs can be reviewed and debugged easily.

MS Sadia Ejaz CIIT ATTOCK


Basic flowchart symbols

Basic Flowchart Symbols

  • Input/Output

    Parallelogram symbol is used to represent an input or output step. Input statement is used to get input from the user. The output statement is used to display a message to the use or to display a value.

Input

Output

MS Sadia Ejaz CIIT ATTOCK


Basic flowchart symbols contd

Basic Flowchart Symbols (contd.)

  • Process

    Rectangle symbol is used to represent a process step.

MS Sadia Ejaz CIIT ATTOCK


Basic flowchart symbols contd1

Basic Flowchart Symbols (contd.)

  • Selection

    Diamond symbol is used to represent a selection step.

MS Sadia Ejaz CIIT ATTOCK


Basic flowchart symbols contd2

Basic Flowchart Symbols (contd.)

  • Start/End

    Oval symbol is used to represent the start or end of the flowchart.

End

Start

MS Sadia Ejaz CIIT ATTOCK


Basic flowchart symbols contd3

Basic Flowchart Symbols (contd.)

  • ConnectorIndicates that the flow continues where a matching symbol (containing the same letter) has been placed.

MS Sadia Ejaz CIIT ATTOCK


Basic flowchart symbols contd4

Basic Flowchart Symbols (contd.)

  • Flow LineLines indicate the sequence of steps and the direction of flow.

MS Sadia Ejaz CIIT ATTOCK


Example1

Example

Start

Input A, B

Sum = A+B

Display Sum

End

MS Sadia Ejaz CIIT ATTOCK


Difference between pseudo code and flowchart

Difference Between Pseudo Code and Flowchart

MS Sadia Ejaz CIIT ATTOCK


Program development process

Program Development Process

  • A programmer has to go through the following stages to develop a computer program:

    • Defining and Analyzing the Problem.

    • Designing the Algorithm

    • Coding or Writing the Program

    • Test Execution

    • Debugging

    • Final Documentation

MS Sadia Ejaz CIIT ATTOCK


Integrated development environment ide

Integrated Development Environment (IDE)

  • Editor

  • Compilers

  • Debugger

  • Linkers

  • Loaders

MS Sadia Ejaz CIIT ATTOCK


Lecture 5 6 introduction to computer programming

Program is created in the editor and stored on disk.

Disk

Preprocessor program

processes the code.

Disk

Compiler creates object code and storesit on disk.

Disk

Compiler

Linker links the object

code with the libraries

Disk

Primary Memory

Loader

Loader puts program in memory.

Disk

Primary Memory

CPU takes each

instruction and executes it, possibly storing new data values as the program executes.

CPU

Preprocessor

Linker

Editor

.

.

.

.

.

.

.

.

.

.

.

.

MS Sadia Ejaz CIIT ATTOCK


Tools of the trade

Tools of the trade

  • Editor

    • First of all we need a tool for writing the code of a program. For this purpose we used Editors in which we write our code.

MS Sadia Ejaz CIIT ATTOCK


Debugger

Debugger

It is used to debug the program.

MS Sadia Ejaz CIIT ATTOCK


Linker

Linker

Most of the time our program is using different routines and functions that are located in different files, hence it needs the executable code of those routines/functions.

Linker is a tool which performs this job, it checks our program and includes all those routines or functions which we are using in our program to make a standalone executable code and this process is called Linking.

MS Sadia Ejaz CIIT ATTOCK


Loader

Loader

Another process which is needed to load the program into memory and then instruct the processor to start the execution of the program from the first instruction (the starting point of every C program is from the main function).

This processor is known as loader.

Linker and loaders are the part of development environment. These are part of system software.

MS Sadia Ejaz CIIT ATTOCK


Debugging in turbo c

Debugging in Turbo C++

An error in a computer program is known as bug.

The process of finding and removing bugs is known as debugging.

MS Sadia Ejaz CIIT ATTOCK


Types of errors

Types of Errors

Syntax Errors

Logical Errors

Run-Time Errors

MS Sadia Ejaz CIIT ATTOCK


Syntax errors

Syntax Errors

It is a type of error that occurs when an invalid statement is written in program.

MS Sadia Ejaz CIIT ATTOCK


Logical errors

Logical Errors

It is a type of error that occurs due to poor logic of the programmer.

MS Sadia Ejaz CIIT ATTOCK


Run time errors

Run-Time Errors

It is a type of error that occurs during the execution of program.

MS Sadia Ejaz CIIT ATTOCK


C statement

C++ Statement

  • The statement of the program are writen under the main() function between the curely bracket{}.

  • These statement are the body of program

  • Each statement of the c++ ends with a semicolon(;)

  • C++ is a case sensitive language

  • The c++ statement are normally written in lowercase letters but in some exceptional but in some exceptional cases, these can also be written in upper case

MS Sadia Ejaz CIIT ATTOCK


Keyword

keyword

  • The words that are used by the language for special purpose are called keywords

  • e.g. in c++ program, the word main is used to indicate the starting of program, include is used to header files, int to declare an integer data type

  • All these words are keyword of c++

  • The keyword cannot be used as variable names in program

MS Sadia Ejaz CIIT ATTOCK


Identifiers

Identifiers

The identifiers are the names used to represent variable, constants, types, functions and labels in the program.

An identifier in C++ may consist of 31 characters.

MS Sadia Ejaz CIIT ATTOCK


Types of identifiers

Types of Identifiers

  • Standard Identifiers

    • A type of identifier that has special meaning in C++ is known standard identifier.

    • For example. cout, cin, etc.

  • User-defined Identifiers

    • The type of identifier that is defined by the programmer to access memory location is known as user-defined identifier.

    • For example, marks, age, etc.

MS Sadia Ejaz CIIT ATTOCK


Keywords

Keywords

Keyword is a word in C++ language that has a predefined meaning and purpose.

They are also known as reserved words.

The total number of keywords is 63.

For example, int, class, etc.

MS Sadia Ejaz CIIT ATTOCK


Data types

Data Types

The data type defines a set of values and a set of operations on these values.

A C++ program may need to process different types of data.

MS Sadia Ejaz CIIT ATTOCK


Data types1

Data Types

Data TypePurpose

intto store numeric values

floatto store real values

doubleto store large real values

charto store character values

MS Sadia Ejaz CIIT ATTOCK


Integer data type

Integer Data Type

Integer data is numeric value with no decimal point or fraction.

Types of IntegersSize in Bytes

int 2

short int2

long int4

unsigned int2

unsigned long int4

MS Sadia Ejaz CIIT ATTOCK


Real data types

Real Data Types

Real data is numeric value with decimal point or fraction.

It is also called floating point number.

Types of RealSize in Bytes

float4

double8

long double10

MS Sadia Ejaz CIIT ATTOCK


Character data type

Character Data Type

char data type is used to store character value.

It takes 1 byte in memory.

The characters are stored in ASCII code form.

ASCII  American Standard Code for Information Interchange.

MS Sadia Ejaz CIIT ATTOCK


Integer overflow and underflow

Integer Overflow and Underflow

  • Integer Overflow

    • It occurs when the value assigned to an integer variable is more than maximum possible value.

  • Integer Underflow

    • It occurs when the value assigned to an integer variable is less than possible minimum value.

MS Sadia Ejaz CIIT ATTOCK


Variables

Variables

A variable is a named memory location or memory cell.

The value stored in a variable is referred by variable name.

MS Sadia Ejaz CIIT ATTOCK


Variables declaration

Variables Declaration

  • The process of specifying the variable name and its type is called variable declaration.

  • Syntax

    • Data typevariable_name ;

    • e.g. int marks ;

MS Sadia Ejaz CIIT ATTOCK


Rules for declaring variables

Rules for Declaring Variables

Variable may include letter, numbers and underscore (_).

The first character of variable must be a letter or underscore _. The use of underscore is not recommended. The variables 9minute, #home and 2kg are invalid.

Blank spaces are not allowed in variable names. The variables my var and your car are invalid.

MS Sadia Ejaz CIIT ATTOCK


Rules for declaring variables contd

Rules for Declaring Variables (contd.)

Both upper and lower cases are allowed. A user-defined variable is conventionally written in lower case. The constants are conventionally written in upper case.

Special symbols cannot be used as variable name.

Reserved word cannot be used as variable name. The names int, void and while are invalid variables.

MS Sadia Ejaz CIIT ATTOCK


Rules for declaring variables contd1

Rules for Declaring Variables (contd.)

A variable can be up to 31 characters long for many compiler. If a variable consists of more than 31 characters, only first 31 characters will be used. The remaining characters will be ignored.

A variable can be declared only for one data type.

MS Sadia Ejaz CIIT ATTOCK


Variable initialization

Variable Initialization

  • The process of assigning a value to a variable at the time of declaration is known as variable initialization.

  • Syntax

    • Data typevariable _name =value;

    • e.g. intn=100;

    • int n= 100 ;

MS Sadia Ejaz CIIT ATTOCK


Tokens

Tokens

  • A program statement consist of variable names, keywords, constant, operator etc, these elements of statement are called tokens

    e.g.

int main(){int x,y;x = 5;

}

MS Sadia Ejaz CIIT ATTOCK


Example2

Example

  • simple program

  • #include< stdio.h >#include< iostream.h >int main(){int x;x = 5; cout << x; return 0;}

MS Sadia Ejaz CIIT ATTOCK


  • Login