PSP Lecture1

8/21/2019 PSP Lecture1

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Lecture #1: Introduction to PSP Problem solving Programming

Quaid-i-Azam University Islamabad

Problem Solving and Programming

Zafar [email protected]


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Course Outline

Sessional# 1

Sessional# 2

Terminal

If time permits

Course Evaluation

Sessional (Each): 12.50%

Quizzes 5%

Assignments 10%

Project 10%

Final 50%

Topic Sessions

Introduction to Problem Solving and Programming 1

Problem Solving Concept for the Computer 2--4

Constants and Variables -- Rules and Data types -- Operators -- Expression and Equality

Logic Structures 5--7

Programming Structures -- Modules and Functions -- Cohesion and Coupling

Local and Global Variables -- Pointers/Parameters/Return Values

Sequential Logic Structures 8--9

Flow Charts -- Sequential Logic

Decision Logic Structures 10--11

Decision Logic Structures [IF, ELSE IF, ELSE] -- Case Logic Structure

Loop Logic Structures 12--14

Counter Loop -- Conditional Loop -- Repeat Until -- Array

Introduction to Programming: Syntactic Constructs

Syntactic and Program Conventions -- Decision Logic and Loop logic Structures 15--18

Function, Parameters and Overloading 19--21

Project Assignment

User Define Data type/ Pointers/ Array and Link List 22--24

File Processing 25--26

Sequential Access

Program Testing and Debugging 27--28

Documentation 29--30

Some additional topics


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Books

Problem Solving and Programming Concepts 7th Ed.

By Maureen Sprankle

How to solve it by Computer.By R. G. Dromey

Algorithm Development and Program Design using C.

By Gary J. Bronson


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Introduction to ComputerSystem

Lecture# 1


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Lecture Objectives

Introduction to Computer Systems

Components of a Computer System Input/Output Devices

Motherboard Processor

Memory Main memory

Secondary memory

Bits and Bytes

Software Types of software


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Introduction to Computer Systems

A data processing machine capable ofperforming computations and makinglogical decisions very fast

A computer is a complex system consistingof both hardwareand softwarecomponents.

Computer System

Hardware Software


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A computer system consists of bothhardware and software components.

The hardwarecomponents of a computer

system are the electronic and mechanicalparts.

The softwarecomponents of a computersystem are the intangible parts: the dataand the computer programs.

Components of a Computer System


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The major hardware components of acomputer system are: Processor

Main memory

Secondary memory

Input devices

Output devices

The processor, main memory, secondarymemory, and power supply are inside thesystems unit/Box.



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Peripheral Devices Keyboard

Mouse

Monitor .. etc Input Devices

Mouse

Keyboard .. etc

Output Devices Monitor

Printer .. etc


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Input/Output Devices

Input and output devices allow the computer system tointeract with the outside world by moving data intoand out

ofthe system.

An input device is used to bring data into the system.

Some input devices are: Keyboard

Mouse

Microphone

Bar code reader

Light pen

An output deviceis used to send data out of the system.


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Some output devices are: Monitor, Printer, Speaker etc

Input/output devices are usually called I/O devices.

They are directly connected to an electronic moduleinside the systems unit called a device controller.

For example, the speakers of a multimedia

computer system are directly connected to a device

controller called an audio card (such as a

SoundBlaster), which in turn is connected to the rest

of the system.

Input/Output Devices


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The terms "input" and "output" say if dataflow into or out of the systems unit.

The picture shows the major hardwarecomponents of a computer system. Thearrows show the direction of data flow.



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Main board, often called motherboard.

All computer Components are attached directlyor indirectly with the motherboard.

The power supplysupplies power for mostof the components.


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The busis a group of wires on the maincircuit board of the computer.

It is a pathway for data flowing betweencomponents.

Most devices are connected to the busthrough a controllerwhich coordinates theactivities of the device and the bus.

Theprocessoris an electronic device about a

one inch square. Inside the square is an even smaller square

of silicon containing millions of tiny electricalparts.



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A processor may contain 100 milliontransistors.

The processor is the "brain" of the computersystem.

It does the fundamental computing within thesystem, and directly or indirectly controls allthe other components.

The processor is sometimes called the

Central Processing Unitor CPU.

Processor

L #1 I d i PSP P bl l i P i


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A CPU contains arithmetic and logic unit(ALU), control unit (CU) and registers.

ALU performs calculations such as addition,subtraction, multiplication and division and

logical operations such as comparing twonumbers.

CU controls the order in which programinstructions are executed.

Registers are high speed memory cells usedto store temporary results produced by ALUas well as certain control information

Processor (cont..)

L t #1 I t d ti t PSP P bl l i P i


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The processor is the brain of the computer.All fundamental computing takes place in theprocessor.

Unlike a human brain, which combines

memory with processing power, a computerprocessor has very little memory.

It must rely on other components to holddata and programs and to save results.

The memory in a computer system is of twofundamental types: Main memory

Secondary memory

Memory



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Closely connected to the processor. contents are quickly and easily changed.

holds the programs and data that theprocessor is actively working with.

interacts with the processor millions of timesper second.

Main memory is where programs and dataare kept when the processor is actively usingthem.

Main Memory



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When programs and data become active,they are copied from secondary memory intomain memory where the processor caninteract with them.

A copy remains in secondary memory.

Main memory is intimately connected to theprocessor, so moving instructions from the

program and data into and out of theprocessor is very fast.

Main Memory (cont..)



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Also called RAM (Random Access Memory). "Random" means that the memory cells can

be accessed in any order.

One megabyteof memory is enough to holdapproximately one million charactersof aword processing document.

Nothing permanent is kept in main

memory.

Main Memory (cont..)



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Connected to main memory through the busand a controller.

The contents are easily changed, but changesare slow compared to main memory.

Used for long-term storage of programs anddata.

Before its data and programs can be used,

they must be copied into main memory.

Secondary Memory (cont..)



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Secondary memory is where programs and data arekept on a long-term basis.

Common secondary storage devices are the harddisk and flash drives.

The hard disk has enormous storage capacitycompared to main memory.

The hard disk is usually contained in the systemsunit of a computer.

Data and programs on the hard disk are organizedinto files.

A fileis a named section of the disk.




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The reason for having two types of storage is this

contrast:

Primary memory Secondary memory

1. Fast Slow2. Expensive Cheap

3. Low capacity Large capacity

4. Works directly with Not connected directly

the processor to the processor




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In both main and secondary memory, information is storedas patterns of bits.

A bitis a single on/offvalue. Only these two values arepossible. The two values may go by different names, suchas true/false, or 1/0. There are many ways in which a bit

can be implemented. One bit of information is so little that usually computer

memory is organized into groups of eight bits.

Each eight bit group is called a byte.

When more than eight bits are required for some data, awhole number of bytes are used. One byte is about enoughmemory to hold a single character.

Bits and Bytes



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Bits and Bytes (cont..)

A is a character and represented in 8 bits as

01000001 in computer

Similarly B represented as 01000010



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Often very much more than eight bits are requiredfor data, and thousands, millions, or even billions of

bytes are needed. These amounts have names, as

seen in the table.

Name Number of Bytes power of 2

Byte 1 20

kilobyte 1024 210

megabyte 1,048,576 220

gigabyte 1,073,741,824 230

terabyte 1,099,511,627,776 240

Bits and Bytes (cont..)



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Computer software consists of both programsand data.

Programs are lists of instructionsfor the processor.

Data can be any information that a program needs:character data, numerical data, image data, audio data, andcountless other types.

The distinction between programs and data is not as clear-cut as you might think, however.

Software



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Fundamental Idea: Both programs and data are saved incomputer memory in the same way.

The electronics of computer memory (both main memory

and secondary memory) make no distinction betweenprograms and data.

Software (cont..)



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There are two categories of programs.

Applicationsoftware (usually called just

"applications") are programs that people use to get

their work done.

Systemssoftware keep all the hardware and

software running together smoothly.

Computers exist because people want to run these

programs.

Types of Software



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Application Programs Systems Programs Word processors Operating system

Game programs Utilities

Spreadsheets Programming languages

Data base systems Data Recovery

Graphics programs Data backup

Web browsers

The most important systems program is the operatingsystem.

The operating system is always present when the computeris running.

It coordinates the operation of all the hardware and softwarecomponents of the computer system.

Types of Software (cont..)



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Application Software

System Software

System Hardware



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The operating system is responsible for startingapplication programs running and finding theresources that they need.

For example, when a command is given for printing

a document, OS allocate the printer to theapplication.

Modern operating systems usually come with agraphical user interface(GUI) that enables users to

easily interact with programs by using windows,buttons, menus, icons, the mouse, and thekeyboard.




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When a computer is first started, the hardware willautomatically load the operating system and start it

running.

This process is called booting.

Once the operating system is running, it is used to

start up application programs.

Starting a Program



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Here is a (simplified) list of what happens when the user(you) starts up an application.1. The user asks to run an application. This could be done by clicking

on an icon, making a menu choice, or other means.

2. The OS determines the name of the application.

3. The OS finds the section of the hard disk where the applicationprogram and where its data are stored.

4. The OS finds an unused section of main memory that is largeenough for the application.

5. The OS makes a copy of the application and its data in that sectionof main memory.

6. The OS sets up resources for the application.

7. Finally, the OS starts the application running.

Starting a Program (cont..)

Documents

PSP Lecture1