introduction to computer and programing

Introduction to Computer and ProgramingThanachat Thanomkulabut

Outline2

Introduction to computer Programming Languages C# Language Overview

Definition of Computer3

Devices for performing computations at high speeds with great accuracy

A machine that can be programmed to manipulate symbols.

A machine that can quickly store and retrieve large amounts of data.

Physical components are known as “Hardware”

Introduction to computer

Computer Categories4

• Desktop Computer• Laptop, Notebook, Netbook• PDA – Personal Digital Assistant

Personal Computer

•High Computation PowerSupercomputer and Mainframe


Computer Systems Hardware

Actual physical machines (equipment) that make up the computer

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Software Programs written

for a specific application are often called softwares


Computer Components

CPU (Central Processing Unit)

Primary storage (memory)

Secondary storage (disks, tapes, etc.) Input devices (mouse, keyboard, etc.) Output devices (screen, printer, etc.)

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Hardware - Process

INPUT

Processing

Primary storage

OUTPUTcommand

Information

result

Secondary

storage


Computer Storage

RAM ROM

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Primary Storage

Secondary StorageRead OnlyNon - Volatile

Can Read/Write

Volatile

Much FasterMore

expensive

SlowerLess

expensive

Computer Storage

Data Representation9

Data in computer is represented in “bit” bit = binary digit

0 or 1 Byte = 8 bits 1 byte can represent many kinds of data

1 byte = 01100001 the above 1 byte represents character “a” or

97 the meaning of 1 byte depends on the

program1 Kbyte = 210 = 1024 bytes1 Mbyte = 220 = 1,048,576 bytes1 Gbyte = 230 = 1,073,741,824 bytes1 Tbyte = 240 = 1,099,511,627,776 bytes


ASCII Table10

Outline11


Programming Languages12

Program A set of instructions for a computer to

follow, written in specific programming language

Types of programming language High-Level Language Assembly Language Machine Language

Programming Languages

Programming LanguagesHigh-level VS Assembly VS Machine Language

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High-level Language Nearly like human word

SUM := A * 2 + ALPHA/3; Assembly Language

Some key words are understandable MULL3 A, #2, RADDL3 R6, R7, SUM

Machine Language Only “0” and “1”

0001100001100011001111 10011000111

Computer itself understands only Machine language

Language translator14

Hello World!

_

High-level language•static void Main( )

{ Console.WriteLine("Hello

World!");}

Interpreter/ Compiler Assembly language

•pushl %ebpmovl %esp, %ebpsubl $8, %espandl $-16, %esp

Machine language• 00011000110001110

0011000111010111100011000110001110

Assembler

Machine


High-Level Languages Procedural

Language Fortran Cobol Basic C Pascal

Object-Oriented Language C++ Java C#C#

Functional Language Lisp

Logic Language Prolog

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Outline16


A simple C# Program17

Grouping using { }

C# Language Overview


A statement must be ended with semicolon “;”



C# syntax is case-sensitive

namespace NAMEspace

Main() main()



White space means nothing

static void Main(string[] args) { Console.WriteLine("Hello World!");}

static void Main(string[] args){Console.WriteLine("Hello World!");}



Anything between /* */ or after // is considered a comment

Comments will not be translated


Program Structure The starting point of the program is:

This is known as the method Main A method is put inside a class A class may be put inside a namespace

static void Main () { ... starting point ... }

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Program Structure In C#

A program can contain several namespaces A namespace can contain several classes A class can contain several methods

In other words Think of a namespace as a container of classes Think of a class as a container of methods

method1method1method2method2

namespacenamespaceClassClass

ClassClass

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Program Structure

For this 204111 course Program with only one class and at most one

namespace For now until sometime before midterm

Program with one method (i.e., Main)

namespace HelloW { class HelloWClass { static void Main () { System.Console.WriteLine("Hello World!"); System.Console.ReadLine(); } }}

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Naming C# allows user to give a name to

something. A user-defined name can be any word

with some rules. Remember!!! C# is a case-sensitive

language.

* Case Sensitive Example

KU ≠ kU ≠KU ≠ kU ≠ kuku


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Naming Rules Letters, digits and underscores(_) First character must be a letter or _ Up to 63 characters long Must not be a reserved word


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Example

name Name

_data

9point

class class_A class_"A"

point9

C# Reserved WordsC# Language Overview

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More Resources How Bits and Bytes Work

(http://www.howstuffworks.com/bytes.htm) Byte (http://en.wikipedia.org/wiki/Byte) Computer hardware

(http://en.wikipedia.org/wiki/Computer_hardware) Software (http://en.wikipedia.org/wiki/Software) Programming language

(http://en.wikipedia.org/wiki/Programming_language)

List of programming languages (http://en.wikipedia.org/wiki/List_of_programming_languages)

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Any question?

introduction to computer and programing

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