Computers & Programming (CSE 102) Course Contents PART I : INTRODUCTION TO COMPUTER Essential Basic Concepts. Data Representation Inside Computer. Computer System Components. Computer Classes. Computer Networks & Internet. Computer Applications. Computer Generations. Computers & Programming (CSE 102)

Computer Networks

Two or more computers connected to exchange data Computer Networks Two or more computers connected to exchange data Networks facilitate the exchange of data very far and very fast Dr.Magdy A. Ahmed - Dr. Yousry Taha Computers & Programming (CSE 102)

Interactive exchange of data, voice, and video Network applications Commercial Bank, travel agency, e-commerce Military Entertainment Interactive exchange of data, voice, and video Dr.Magdy A. Ahmed - Dr. Yousry Taha Computers & Programming (CSE 102)

Local Area Network (LAN) Metropolitan Area Network (MAN) Categories of Network Local Area Network (LAN) Connect computers within small area (1 km) Metropolitan Area Network (MAN) Connect computers within medium area (about 10 km) Wide Area Network (WAN) Connect computers within vast area Dr.Magdy A. Ahmed - Dr. Yousry Taha Computers & Programming (CSE 102)

Why we use computer Networks? Access data and applications in remote computers Resources Sharing Reliability Scalability Providing services (E-Mail) - (Chatting) - (Video Conferencing) - (Social Networking) Dr.Magdy A. Ahmed - Dr. Yousry Taha Computers & Programming (CSE 102)

Communication Elements Sender Receiver Message Communication channel Direct link Switching nodes Dr.Magdy A. Ahmed - Dr. Yousry Taha Computers & Programming (CSE 102)

Data Transmission media Wireless Wired Dr.Magdy A. Ahmed - Dr. Yousry Taha Computers & Programming (CSE 102)

Computers & Programming (CSE 102) Internet History 1969 - 4 connected devices (ARPANET) 1972 – 72 connected devices 1982– 254 connected devices Now it has millions of devices world wide and called “Internet” Services Social Networking Web Searching Electronic Mail or E-mail File Transfer Protocol (FTP) Telnet (remote login) Computers & Programming (CSE 102)

Program Development and Programming Languages

Software Development Life Cycle (SDLC) To have a well defined approach to develop and maintain software Software Development Life Cycle (SDLC) is: 1-Problem Analysis 2-Program Design 3-Program Coding 4-Program Debugging and Testing 5-Program Maintenance Dr.Magdy A. Ahmed - Dr. Yousry Taha Computers & Programming (CSE 102)

SDLC : 1- Problem Analysis Define and understand the problem   Inputs Outputs User requirements System requirements Project schedule Start thinking in programming tools Input Output Requirements SW tools Schedule Dr.Magdy A. Ahmed - Dr. Yousry Taha Computers & Programming (CSE 102)

Computers & Programming (CSE 102) SDLC: 2- Program Design Designers suggest how to solve the problem Algorithm Sequence of deterministic steps to solve the problem  Pseudocode Represent the solution in a form like the high level language It is free from the technical details It is easy to convert it to high level language program  Flowchart It represents the algorithm by standard symbols Computers & Programming (CSE 102)

Pseudocode vs Flowchart Convert a length in meter to length in centimeter Pseudocode Read length in meter Multiply length by 100 Write length to represent its value in centimetre Start End Read length in meter Write length in centimetre Length in cm = 100 * length in m Flowchart Computers & Programming (CSE 102)

Computers & Programming (CSE 102) SDLC: 3- Program Coding To convert the algorithm to a program using a programming language SDLC: 4- Program Debugging and Testing To ensure the program is bug free and execute correctly Debugging To check that the code has no: Compile-Time Errors Run-Time Errors Logical Errors (the hardest) Testing To test the program using designed test data We should test all scenarios and all possible cases Computers & Programming (CSE 102)

SDLC: 5- Program Maintenance It starts after using the program To fix bugs discovered in real environment To satisfy new user requirements To satisfy new changes in the problem To adapt with new technology in SW and Computing environment Documentation All development steps should be documented It helps programmers and review and improve their systems It helps new programmers to maintain old systems Computers & Programming (CSE 102)

Computers & Programming (CSE 102) Flowcharts One of the common method to design algorithm Standard symbols are used for representation Symbols are connected by Flow lines Computers & Programming (CSE 102)

Basic symbols of Flowchart Terminal Computational Step (process)  Input / Output Decision Making Predefined Process Connector start end Z = X + Y Input X X > Y Abs(x) 1 2 Computers & Programming (CSE 102)

Flowcharts Control Structures . All algorithms could be built using: Sequential structure Conditional structure Looping structure Read length in meter Length in cm = 100 * length in m Computers & Programming (CSE 102)

Examples Write a program to ask the user for the width and length of a piece of land and then tell him how many orange trees he can grow on it. Given that each orange tree requires 4 m2.

Examples Write a program to ask the user for the radius of a circle, and then display its area and circumference.

Flowcharts Control Structures All algorithms could be built using: Sequential structure Conditional structure Looping structure T F Computers & Programming (CSE 102)

Example Write a program to ask a student for his grades in 3 exams ( each out of 50 ) , get their total and inform the student whether he passed or failed the course.

Flowcharts Control Structures All algorithms could be built using: Sequential structure Conditional structure Looping structure T F For I=1 to 10 Next I Computers & Programming (CSE 102)

Example Assume you put 1000 pounds in a projects that returns a profit of about 5% per year. How long will it take for your money to double ? Assume you put 5000 pounds in a projects that returns a profit of about 10% per year. How much money will you have in 5 years ?

Computers & Programming (CSE 102) Example: Input A, B X=A SUM=0 X<=B SUM=SUM+X X=X+5 Print SUM Start End No Yes Design an algorithm to print out the sum of all numbers between A and B and divisible by 5 (where A is a multiple of 5) Computers & Programming (CSE 102)