Wednesday, December 7, 2011
Introduction To Object Oriented Programming
Introduction To Object Oriented Programming
By: razi.smartcomputing123@gmail.com
OOP Concept
The following part is extracted from: http://en.wikipedia.org/wiki/Object-oriented_programming
What is Object Oriented Programming?
Object-oriented programming (OOP) is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs.
What is Programming Paradigm?
Programming Paradigm simply means the way programmers look at problem solving approach using computers.
Example type of paradigm
Procedure Oriented Programming, i.e. Programmers writes instructions in block of codes that carry out specific action.
This paradigm has some limitations and OOP concept is now receiving attention.
What does “object” in OOP mean?
Object is a kind of Data Structure that consists of data (properties) and procedures (methods) to work with them.
Object is the natural way we recognize entities in the real world, for e.g, a postman (an object) is a person (known by his name and employee number) that delivers parcels (his associated role)
What are other examples of “Object”?
A Washing Machine
Properties: (Machine Serial Number, Wash_Type, Rinse_Type, Spin_Type)
Methods: (Wash, Rinse, Spin)
Exam Session Manager;
Properties: (Exam Date, Subject, Candidate_Lists, Session_Status)
Methods: (Register_Candidate, Run_Session, Close_Session)
What is the problem of non-OOP program?
Simple, non-OOP programs may be one "long" list of statements (or commands).
More complex programs will often group smaller sections of these statements into functions or subroutines each of which might perform a particular task.
With designs of this sort, it is common for some of the program's data to be 'global', i.e. accessible from any part of the program.
As programs grow in size, allowing any function to modify any piece of data means that bugs can have wide-reaching effects.
How does OOP address the ‘global’ data issue in non-OOP program?
object-oriented approach encourages the programmer to place data where it is not directly accessible by the rest of the program.
Instead, the data is accessed by calling specially written functions, commonly called methods, which are either bundled in with the data.
This protects the consistency of the data.
The following part is extracted from: http://www.jrobbins.org/ics121f03/lesson-uml-structure.html
OOP and UML Modeling
Why make models?
Software systems are very complex and hard to understand
Models are abstractions of systems:
They express certain aspects of the system and ignore others
They are less complex and easier to understand
Models can make certain aspects more clearly visible than in the real system
What can you do with models?
Express your ideas and communicate with other engineers
Reason about the system: detect errors, predict qualities
Generate parts of the real system: code, schemas
Reverse-engineer the real system to make a model
What is UML?
Unified Modeling Language
A modeling language standardized between 1995 and 1997 by Rational, IBM, HP, Microsoft, Oracle, MCI, Unisys, DEC, and others
“Unified” means:
Unified existing approaches to OO design notations: Booch, OMT, Objectory, and Statecharts
Unified notation used in multiple phases of development: Requirements, design, and implementation
Unified industry interest, training, and skills/job market
The UML notation consists of:
Class diagrams
Object diagrams
Use case diagrams
Collaboration diagrams
Sequence diagrams
Statechart diagrams
Activity diagrams
Component and deployment diagrams
UML Class Diagram
Class Diagram shows the structure of a class (template for object), i.e the Class Name, Properties and Methods
WASHING MACHINE
Machine_No
Wash_Type
Rinse_Type
Spin_Type
Wash()
Rinse()
Spin()
EXAM SESSION MANAGER
Exam_Date
Exam_Subject
Candidate_Lists
Session_Status
RegisterCandidate()
RunSession()
CloseSession()
UML Use Case Diagram
Use Case Diagram shows the behavior of an object
Washing
Machine
Wash
Rinse
Spin
Exam Session Manager
Register
Run
Close
Sunday, December 4, 2011
Saturday, December 3, 2011
Basic Problem Solving Using Computers 1
By: razi.smartcomputing123@gmail.com
Pre-requisite
You are expected to know the following topics before moving to the next slides. Click the links to learn more about them.
What is Computer Programming? (learn more)
What is ideone.com compiler? (learn more)
How to write the basic program structure? (learn more)
Introduction
This presentation demonstrates the concept of problem-solving using computer machine.
All codes can be tested on ideone.com compiler.
What are the advantages of using computer to solve problem?
Computer processing is fast,
millions instructions executed per second
Computer is a reliable processing agent;
it follows instructions exactly as they are.
Computer is consistent;
no such thing as tiredness,
Computer has efficient memory;
huge data collection can be kept in relatively small physical space.
Types of problem that can be solved through programming
Problem can be solved through programming if it can be expressed either as
Arithmetic form, or
Logic form
To perform computer processing we need…
Algorithm
Steps to perform processing
Data Structures
To hold the values prior to, during and post processing
Control Structures
To control program statement execution
These 3 elements are required for computer processing
Algorithm
Narrative Format (Pseudo-Code)
BEGIN
READ integer1, integer2
LET integer3=integer1 + integer2
PRINT integer3
END
Visual Format (Flow Chart)
BEGIN
READ integer1, integer2
LET integer3=integer1 + integer2
PRINT integer3
END
Data Structure
Describe the structure that contains the data value.
Must be designed correctly to achieve efficiency.
Basic data types:
Numbers; integer or decimal point
Text; a character or strings (group of characters)
Compound data types:
Array
Control Structures
Later, we shall see some variations of control structures to add programming flexibility
Problem 1 : Finding area of dimensions
The following table provides a mathematical formula to calculate area for various shapes. Write a program to implement this.
Shape
Formula
Input Values
Rectangle
length x width
Length=5, width=6
Triangle
½ x length x width
Length=3, width=4
Circle
PI x r2
R=2.4
Solution 1a. Area of rectangle
C++
#include «iostream»
using namespace std;
int main() {
int length, width,rectangle;
length=5;
width=6;
rectangle=length * width;
cout«« "area= "««rectangle;
return 0;
}
VB.net
Imports System
Public Class Test
Public Shared Sub Main()
Dim length,width,rectangle as integer
length=5
width=6
rectangle=length * width
Console.WriteLine("area= " & rectangle)
End Sub
End Class
Line 4 declares integer variables. Line 5,6,7 sets the value of the variables. Line 8 outputs the result.
Solution 1b. Area of triangle
C++
#include «iostream»
using namespace std;
int main() {
double length, width, triangle;
length=5;
width=6;
triangle=0.5 * length * width;
cout«« "area= "««triangle;
return 0;
}
VB.net
Imports System
Public Class Test
Public Shared Sub Main()
Dim length,width,triangle as double
length=5
width=6
triangle=0.5*length * width
Console.WriteLine("area= " & triangle)
End Sub
End Class
Line 4 declares integer variables. Line 5,6,7 sets the value of the variables. Line 8 outputs the result.
Solution 1c. Area of circle
C++
#include «iostream»
using namespace std;
int main() {
double PI, radius;
PI=3.14;
radius=2.4;
circle=PI * radius * radius;
cout«« "area= " ««circle;
return 0;
}
VB.net
Imports System
Public Class Test
Public Shared Sub Main()
Dim PI, radius as double
PI=3.14
radius=2.4
circle=PI * radius * radius
Console.WriteLine("area= " & circle)
End Sub
End Class
Line 4 declares integer variables. Line 5,6,7 sets the value of the variables. Line 8 outputs the result.
Problem 2 : Assigning Grades
Student marks range from 0 to 100
Their marks correspond to the grades based on the table below.
Write a program to assign grades to the input marks value.
Min Value
Max Value
Grade
0
39
F
40
59
C
60
79
B
80
100
A
Solution 2. Grades
C++ (http://ideone.com/mO3Lr)
#include «iostream»
using namespace std;
int main() {
double marks;
char grade;
cin»» marks;
if ((marks»=0) && (marks«=39)) {grade='F';}
if ((marks»=40) && (marks«=59)) {grade='C';}
if ((marks»=60) && (marks«=79)) {grade='B';}
if ((marks»=80) && (marks«=100)) {grade='B';}
cout««grade;
return 0;
}
VB.net (http://ideone.com/RirLS)
Imports System
Public Class Test
Public Shared Sub Main()
Dim marks as double
Dim grade as string
marks=val(console.ReadLine())
if ((marks»=0) and (marks«=39)) then grade="F"
if ((marks»=40) and (marks«=59)) then grade="C"
if ((marks»=60) and (marks«=79)) then grade="B"
if ((marks»=80) and (marks«=100)) then grade="B"
Console.WriteLine(grade)
End Sub
End Class
Line 4,5 declares integer variables. Line 6 gets the input value. Line 7,8,9,10 selectively sets the value of the variables. Line 8 outputs the result.
Problem 3 : Login Module
You are required to write codes for login process.
The input_pin value will be compared against the pin value (hardcoded as 1234)
Login trials is limited to 3 times only.
Use WHILE DO(…) LOOP to implement the solution.
Solution 3. Login Module
C++ (http://ideone.com/0CuYI)
#include «iostream»
using namespace std;
int main() {
int pin, input_pin;
int trial,logged;
trial=0;
logged=0;
pin=1234;
while ((trial«3) && (logged==0)) {
cin»»input_pin;
if (input_pin==pin) {
logged=1;}
else {
logged=0;
}
cout««"Trial:"««trial««",Logged:"««logged««endl;
trial++;
}
return 0;
}
VB.net (http://ideone.com/GsXo4)
Imports System
Public Class Test
Public Shared Sub Main()
Dim pin, input_pin as integer
Dim trial, logged as integer
trial=0
logged=0
pin=1234
While (trial«3) and (logged=0)
input_pin=val(console.ReadLine())
If (input_pin=pin) Then
logged=1
Else
logged=0
End If
Console.WriteLine("Trial:" & trial & ",Logged:" & logged)
trial +=1
End While
End Sub
End Class
Line 4,5 declares integer variables. Line 6,7,8 sets initial value for variables. Line 10 gets the input value. Line 11-15 evaluates the input and sets the logged value. Line 9-10 contains the WHILE () DO ...LOOP
Next topics:
More Control Structures
Friday, December 2, 2011
Writing basic program structure using ideone.com compiler
By: razi.smartcomputing123@gmail.com
Pre-requisite
You are expected to know the following topics before moving to the next slides. Click the links to learn more about them.
What is Computer Programming? (learn more)
What is ideone.com compiler? (learn more)
Introduction
This presentation demonstrates the application of basic control structure using C++ and VB.net language.
All codes can be tested on ideone.com compiler.
3 Basic Control Structures
Source Code Templates
C++
#include «iostream»
using namespace std;
int main() {
return 0;
}
VB.net
Imports System
Public Class Test
Public Shared Sub Main()
End Sub
End Class
The followings are the source code templates that is provided by ideone.com
Use this template as a starting point for you to do the programming exercises.
Sequential Control Structure
C++
#include «iostream»
using namespace std;
int main() {
cout««"Hello World"««endl;
cout««"........... "««endl;
return 0;
}
Sequential Control Structure is the default control structure, i.e computer execute statements one after another in top-down direction unless told otherwise.
The following codes display “Hello World” on the first line and dots on the second line.
Sequential Control Structure
Visual Basic .NET
Imports System
Public Class Test
Public Shared Sub Main()
Console.WriteLine("Hello World" & vbCrLf)
Console.WriteLine("..........." & vbCrLf)
Console.ReadLine() 'Wait for key to be pressed
End Sub
End Sub
Sequential Control Structure is the default control structure, i.e computer execute statements one after another in top-down direction unless told otherwise.
The following codes display “Hello World” on the first line and dots on the second line.
Sequential Control Structure & Variable Declaration
C++
#include «iostream»
using namespace std;
int main() {
int num1;
int num2;
int num3;
num1=1;
num2=2;
num3=num1+num2;
cout««"The output is "««num3««endl;
return 0;
}
Line 4,5,6 declare integer variables. Line 7,8,9 assign values to them. Line 10 outputs the value.
Sequential Control Structure & Variable Declaration
Visual Basic .NET
Imports System
Public Class Test
Public Shared Sub Main()
Dim num1 as integer
Dim num2 as integer
Dim num3 as integer
num1=1
num2=2
num3=num1+num2
Console.WriteLine("The output is " & num3 & vbCrLf)
End Sub
End Class
Line 4,5,6 declare integer variables. Line 7,8,9 assign values to them. Line 10 outputs the value.
Selection Control Structure
C++
#include «iostream»
using namespace std;
int main() {
int iMark;
iMark=50;
if (iMark»=40) {
cout««"Pass!"««endl;}
else {
cout««"Failed!"««endl;}
return 0;
}
Line 5 assigns the value for iMark. Line 6 evaluate whether the value is greater than or equals to 40. If TRUE, PRINT “Pass!”. Otherwise, PRINT “Failed!”
Selection Control Structure
Visual Basic .NET
Imports System
Public Class Test
Public Shared Sub Main()
Dim iMark as integer
iMark=50
if (iMark»=40) then
Console.WriteLine("Pass!" & vbCrLf)
else
Console.WriteLine("Failed!" & vbCrLf)
end if
End Sub
End Class
Line 5 assigns the value for iMark. Line 6 evaluate whether the value is greater than or equals to 40. If TRUE, PRINT “Pass!”. Otherwise, PRINT “Failed!”
Loop Control Structure
C++
#include «iostream»
using namespace std;
int main() {
int iMark;
iMark=30;
while (iMark«40) {
cout««iMark««endl;
iMark++;
}
return 0;
}
Line 5 assigns the value for iMark. Line 6 evaluate whether the value is less than 40. If it is TRUE, run a loop and add 1 to iMark in each loop. Line 8 uses increment operator ++
Loop Control Structure
Visual Basic .NET
Imports System
Public Class Test
Public Shared Sub Main()
Dim iMark as integer
iMark=30
do while (iMark«40)
Console.WriteLine(iMark & vbCrLf)
iMark+=1
loop
End Sub
End Class
Line 5 assigns the value for iMark. Line 6 evaluate whether the value is less than 40. If it is TRUE, run a loop and add 1 to iMark in each loop. Line 8 use increment operator +=
Summary
We have learned:
Console window output via ideone.com
3 basic control structures:
Sequential
Selection [IF … ELSE …]
Loop [WHILE (…) DO …]
Increment operator
Newline character
Next topics:
SWITCH SELECTION
DO (…) WHILE (…) LOOP
FOR LOOP
What is Computer Programming
By: razi.smartcomputing123@gmail.com
What is Computer Programming?
Computer Programming is …
the activities of writing set of instructions that will be executed by a computer machine.
A person who writes computer program is called …
a programmer.
Programming Activities
Programming activities involves:
Analyze user requirement
Design the program
Code the program
Test the program
Operate the program
1.Analyze User Requirement
Finding out:
What is the problem to be solved?
What are the constraints associated with the program?
What is the input/output that the program should get/produce?
Set the program objectives
INPUT
PROCESS
OUTPUT
integer1,
integer2
LET integer3 =sum of integer1 and integer2
integer3
A simple Input-Process-Output box showing the user requirement
2. Design The Program
Narrative Format (Pseudo-Code)
BEGIN
READ integer1, integer2
LET integer3=integer1 + integer2
PRINT integer3
END
Visual Format (Flow Chart)
BEGIN
READ integer1, integer2
LET integer3=integer1 + integer2
PRINT integer3
END
3. Code The Program
#include «iostream»
Using namespace std;
Int main(void){
int integer1,integer2,integer3;
cout««“Enter two integers:”;
cin»»integer1;
cin»»integer2;
integer3=integer1+integer2;
cout««“The sum is:”;
cout««integer3;
system(“PAUSE”);
return 0;
}
Enter two integers:
1
2
The sum is:
3
C++ Source Code Sample
C++ Console Output Sample
4. Test The Program
Test Case is …
a list of input values to be given to the program during runtime together with the expected outcome from the computer.
This helps to …
check whether a program is running according to its specified objectives.
(Test Cases for the program design in the previous slides)
5. Operate The Program
Install to the targeted platform
Training and support
Maintenance
Many types of programming languages
Programming languages…
Language used to construct the program codes
Various types exist…
To support different needs, focus and orientation of programming works
Popular ones are …
C, C++, Java, Visual Basic etc.
Programming Paradigm
The way programmer looks at problem-solving using computers
Procedure-oriented
Program is build from combination of code blocks (procedures)
Object-oriented
Problem-solving involves interaction between entities (objects) that incorporate data and functions.
Commonly Used Paradigm
Procedure-oriented programming
Why?
Simple
Easy to learn and apply
Practical
Available as…
Standalone (C++)
Script (VBA)
Which Language To Start?
It could be …
C++
It provides a starting point before moving to other languages such as Java, PHP etc.
Visual Basic
It provides a starting point for windows-based platform
Or whatever language that you may have found suitable reference and instructor to begin with :-)
Microsoft released a Visual Basic for kids called “Small Basic”
It is so ‘basic’ that a person could easily learn programming
Program Control Structures
Defines how program codes/statements should be executed by computer.
Generally…
Sequential
Execute from top to bottom (default)
Selection
Selectively Execute certain statements
Loop
Repeatedly Execute certain statements
Sequential Control Structure
Statements are executed one after another in a top-down direction.
Selection Control Structure
When the program control reaches a CHOICE point(diamond symbol), it must decide which branch to execute next.
Decision is based on the conditional statement (logic value, i.e TRUE or FALSE) that is placed at CHOICE point.
Loop Control Structure
When a program control reaches a CHOICE point, it must repeatedly execute certain instructions until a loop terminating condition is met.
The terminating condition can be determined either during programming or runtime.
Next?
Let’s start the coding!
Thursday, December 1, 2011
Visit - ideone.com
What is ideone?
Ideone is something more than a pastebin; it's an online compiler and debugging tool which allows
to compile and run code online in more than 40 programming languages.
How to use ideone?
Choose a programming language, enter your source code and input data into text boxes. Then check or uncheck run code(whether to execute your program) and private (whether not to list your code in the recent codes page) checkboxes, click the submit button and watch your snippet being executed.
Having problems?
Check the samples to see how to write a properly working code. To find out more, see the help section or the FAQ page.
Ideone is something more than a pastebin; it's an online compiler and debugging tool which allows
to compile and run code online in more than 40 programming languages.
How to use ideone?
Choose a programming language, enter your source code and input data into text boxes. Then check or uncheck run code(whether to execute your program) and private (whether not to list your code in the recent codes page) checkboxes, click the submit button and watch your snippet being executed.
Having problems?
Check the samples to see how to write a properly working code. To find out more, see the help section or the FAQ page.
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