Programming language concept INSY210.A11 Dr. Feng Liu

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Programming language concept

• INSY210.A11
• Dr. Feng Liu

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Lecture1 Introduction to CS and Programming
languages
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Outline

• Introduction to Computers
• Computer System
• Hardware
• Software
• Computer language
• Programming
• System development

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Computer system
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Hardware
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Computer Software
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Relationship
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Computer system environment
(A)
(B)

• Personal computer
• (B) Client Server System
• (C) Distributed computing

(C)
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Computer language
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Computer language

• Machine Language
• 010111001011
• all the components have only two status
• Switch on 1
• Switch off 0
• The only language machine can understand

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Computer language

• Symbolic languages (Assembling language) special
  machine order
• Grace Hopper invent the language
• entry main
• pushal (r2)

Assembler
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Computer language

• High-level language
• C /C
• Java
• XML
• VB . etc

Natural Language
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From high-level lanuage to machine language

• High-level language like C
• write and edit code on a text editor (source
  file)
• Compile with preprocessor translator
• Link with lib fundtions

Object Module
Object Module
Std Libfunctions
Linker
Compiler
Source file
Object Module
preprocessor
translator
0111001010 1010010010 1010010010 0100101001 001010
1100 1110011010
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(No Transcript)
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System development

• Waterfall model
• System requirement
• System analysis define
• system requirements
• System goal
• Analysis
• Different options
• Design
• How to build the system
• Individual program define
• Coding
• Write the program
• Testing check the satisfaction
• Maintain keep system works and up to date

Spend more time here Will save the code rewriting
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Programming process

• Take the requirement and design of the interface
• Understand where you program will fit the the
  whole picture
• Your program take the INPUT and Convert it to a
  desired OUTPUT

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Tools for developing solution

• Structure Chart
• Pseudocode
• A precise algorithmic description of program
  logic.
• Flowchart
• Example
• Calculate the sqft of your house

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Structure chart
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Pseudocode for calculate bathroom

• Algorithm for calculate bathroom
• Prompt to user and readin unit price of material
• Prompt to user and readin number of the bathrooms
• Set total area of bath to zero
• While (baths processed lt total number of the
  bathrooms)
• Prompt user and readin bath length and width
• Total bath area Total bath area bath length
  bath width
• Add 1 to baths processed
• End loop
• Bath cost total area unit price
• Return bath cost
• End of the Algorithm for calculate bathroom
• Refer to the flowchart for calculate bathroom
  Figure 1-14

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Testing

• one set of test data will never enough
• Two type of testing
• Blackbox testing
• Whitebox testing
• Testing have no end

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Outline

• Introduction to the C language
• Background
• Structure of C programming
• First program
• Identifiers
• Data types
• Variables
• Constant
• Cin, Cout

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Structure of C programming

• Global definition can be access anywhere
• One program have only one main()
• Subfunction can be call by another function

Subfuntion
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First program

• Pre-compiler directives include header file ltgt
• Namespace create a space organize the name and
  tell compiler where to find it
• using namespace std

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Comments
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Identifiers

• Rules
• AZ, aZ , 0 9, _
• No start with digital
• Can not use reserved word (appendix B on the
  book)
• Example int
• Convention
• worker_group
• workerGroup

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Data Types

• Standard data types
• Derived data types pointer, class, structure,
  array

True 1 false 0
No value, no operation
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Integer

• A number without fraction part.
• How big could be the int is depend on each of the
  machine.
• Example short int on 16bit
• signed - 2 15 2 15
• unsigned 0 2 16

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Char

• A char is any value that can be represented in
  computer alphabet.
• Example
• Char a
• Binary 01100001
• Decimal 97
• Refer to ASCII table (Appendix App860)

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Floating

• Float
• Byte size 4
• Number of bits 32
• Example interest rate 5, or 0.05
• Double
• Byte size 8
• Number of bits 64
• Example PI 3.1415926

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Variable

• Variable declaration
• Variable type variable identifier
• int a
• float a, b, c
• Variable initialization
• int a 0
• float a, b, c 20.0
• char c1 h

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Constant

• Define a constant
• define SALES_TAX_RATE .825
• Named constant
• const float pi 3.14
• Stored in memory with significant part and
  exponent part
• Can not be access and modified

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Character Constant

• a character a
• Escape Character (\) used when you need to
  present does not have the graphics associated
  with it.
• Example
• \n new line
• \t tab
• \ single quote
• \\ - backslash
• See more details in pp42

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String Constants

• String constant is a sequence of zero or more
  characters enclosed in double quotes.
• Example
• hello world!!
• How to print the following sentence?
• Good morning! the teacher said.

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Standard streams

• The standard streams are created automatically
  and connected to appropriate devices when a
  program starts
• You need to have std stream declared as
• include ltinstreamgt
• Then you can use the iostream in the program,
  otherwise, error!!
• cout ltlt Hello class!, hope you have fun so
  far!\n
• cout ltlt See you next time!!

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Intro to C programming