Fundamentals of Programming - · PDF fileFundamentals of Programming Course Structure ... • Linker—combines the compiler- ... runs the program –Java class libraries

Fundamentals of Programming

Budditha HettigeDepartment of Computer Science

Fundamentals of Programming

Course Structure• Lectures

– 30 Hours

• Practical /Tutorials

– 30 hours

• Assignment (30%)

– Practical Test (10 marks)

– Quizzes 4 (Get maximum 2 ) (10 x2 = 20 marks )

– Total 30%

• Final Examination (70 %)

– 4 Questions (3 hours) (70%)

• Reference:– https://budditha.wordpress.com/

7/11/2015 Budditha Hettige ([email protected]) 2

Course Structure

• Introduction

• Steps to Computer Programming

• Introduction to Java

• Input and output

• Variables

• Selections (if, switch)

• Loops (for, while, do-while)

• Methods• To-Down Design• Arrays

• Console application

• Menu driven application development3Budditha Hettige ([email protected])

Introduction to Programming


Why people use machines?


Machines• Café Machine make a tea

• ATM machine money transaction

• Calculator solve equation

• Each Machine has …

– Input

– Output

– Process

6Budditha Hettige ([email protected])

input Process Output

Café Machine

• Input– Sugar

– Water

– Coffee

– Milk

• Output– Tea

• Process– ????

Input

Output

Process


ATM machine

• Input– ???

• Output– ???

• Process– ???


Calculator

• Input– ???

• Output– ???

• Process– ???


Process of a Machine

• Work through the instructions given to it– Read

– Write

– Do some calculations

– Go to next instruction

• The sequence of instructions is call a

Program

• Program is a story to tell some task to others


What is a Programming?

• Programming is the way to give instructions

• Each program has– Start

– Some work

– End

• Program is given/execute through the machine understood language


A Computer

• Machine that can solve problems for

people by carrying out instructions given to it

• The sequence of instructions is called Program

• The language machine can understand is called machine language


Machine Language

• Machine language is a set of instructions

executed directly by a computer's central processing unit (CPU)


Machine Language contd..

• Advantages– Machine can directly access (Electronic circuit)

– High Speed

• Disadvantages– Human cannot identify

– Machine depended

(Hardware depended)


Computer Language(s)

• Artificial Languages

• Human readable

• Ex: C/C++, Java

Programming Language(Ln)

Machine Language (L0)

Translator/ Interpreter

Machine

Programming

Language(Ln)

Machine Language

(L0)


Interpretation

• Each instruction in L1 can execute through the relevant L0 instructions directly

• Program is call interpreter

• Two languages are needed to closely

related

• Example:

• Sinhala – English

• Sinhala - Pali


Translator (L1 L0)

1. Replace each instruction written in L1 in to LO

2. Program now execute new program

3. Program is called compiler/ translator


Compilers

• Translate high-level language to machine language

• Input (Source code)– The original program in a high level language

• Output (Object code/ Machine Code)– The translated version in machine language

• Example– C++ compiler, JAVA Compiler etc.


Programming steps


• Compilers. A compiler translates the source code to target code

• Preprocessor—adds to or modifies the contents of the source file before the compiler begins processing the code

• Linker—combines the compiler-generated machine code with precompiled library code orcompiled code from other sources to make a complete executable program

Programming language

generations

This classification is used to indicate increasing power of programming styles

1. First-generation programming languages

2. Second-generation programming languages

3. Third-generation programming languages

4. Fourth-generation programming languages

5. Fifth-generation programming languages


First-generation programming

language (1GL)• Is a machine-level programming language

• Translator isn’t used to compile

• The instructions in 1GL are made of binary numbers, represented by 1s and 0s

• Advantage

– The code can run very fast and very efficiently

because the instructions are executed directly by the CPU

• Disadvantage

– When an error occurs, the code is not as easy to fix


Second-generation

programming language(2GL)

• Assembly language.

• Properties

– The code can be read and written by a programmer

– The language is specific to a particular processor family and environment

• Used in kernels and device drivers


Third-generation programming

languages (3GL)• Languages are more programmer-friendly

• Example

– C, C++, C#, Java, BASIC and Pascal

• Support structured programming.

• Must be translated into machine language by a compiler or interpreter

• Advantages

– Easier to read, write, and maintain


Fourth-generation programming

languages(4GL)• Designed to reduce programming effort

• Consist of – Set of libraries

– CRUD generators

– Report generators

– DBMS

– Visual design tool and integration API

• Different types of 4GLs– Table-driven (codeless) programming

• PowerBuilder

– Data management• SAS, SPSS

– Report-generator programming languages • Oracle Developer Suite


Fifth-generation programming

language(5GL)

• Based on solving problems using constraints given to

the program, rather than using an algorithm written by a programmer

• Use mainly in Artificial Intelligence research

• Example– Prolog, OPS5, and Mercury


Selecting a suitable Computer

Language

• Readability

• How easy to write the program in this particular language?

• Reliability

• How much would it cost to develop using a given language?

• How complicated the syntax going to be?

• Does the language have standards for greater readability?


Example

• Assembly Language Program– Device drivers, Virus

• C / C++ Program– Device drivers , DLLs

• JAVA / Visual C++ Program– Desktop applications, Web Applications

• Prolog– AI based applications, Games, Translators


Exercise

• To solve the following problems, identify the input, output and the process

Find the area of a room

Search a place of a city

Calculate grade for the given mark

Get some amount from ATM machine


input Process Output

Stages of Computer

Programming1. Planning

2. Analysis

3. Design

4. Implementation

5. Testing

6. Maintenance and update


Planning

• Identify scope of the project

• Estimate the work involved

• Create a project schedule

• Begins with requirements that define the software to be developed.

• The project plan can be used to describe the task


Analysis

• Is a complete description of the behavior of a system

• Consist of – Functional requirements

– Non-functional requirements

• Methods– Interview

– Questionnaires

– Observation etc.


Software Design

• Software design is a process of problem-solving and planning for a software solution

• Types– Top down

– Bottom up

– Module design

• Use to describe– Algorithm

– Flowchart

– Pseudo code


Design process


Design cont.…

• Flowchart:– is a type of diagram that

represents an algorithm or process

– Gives diagrammatic

representation solution to a given problem

– Use in analyzing, designing,

documenting or managing a process or program


Flowchart- building blocks


Flowchart-building blocks

contd...


Example


Example

• Draw a flow chart to display total of the two numbers


Example

• Draw a flow chart to identify correct login for the following interface


Implementation

• Is a realization of a technical specification or

algorithm as a program, software component through computer programming

• May exist for a given specification or standard– Example World Wide Web Consortium-recommended

specifications

• After implement– Source code, together with documentation to make

the code more readable.


Program Testing

• is an investigation conducted to provide

information about the quality of the product

• A primary purpose of testing is to detect software failures

• Test– White box test

– Black box test


Program Maintenance and

Update

• Is the modification of a software product after delivery to correct faults

• Maintenance may span for 20 years, whereas development may be 1-2 year

• User guide, Maintenance manual need to provides

• Example– Windows XP (Development few years, Maintenance ….)

– Provides set of software updates patches etc.


The Characteristics of a Good

Computer ProgramReliability:

The program should provide correct results at all times and should be free from errors.

Maintainability:

The existing program should be able to change or modify to meet new requirements.

Portability:

The program should be able to transfer to a different computer system.

Readability:

The program must be readable and understandable with the help of documentation.

Performance:

The program should handle the task more quickly and efficiently.

Storage saving:

The program should be written with the least number of instructions


Steps to Computer programming

• Identify Input, Output and process

• Make a design

• Use suitable programming language and implement your system

• Test your program


Activity

• You are required to design a software solution for a

small library explain each steps of the software

development

1. Identify requirements

2. Write project proposal

3. Make Complete Design

4. Implement a solution

5. Test solution


Design


Another Approach


Software Quality


Questions


Tools & Tips for

Computer programming

• Source code Editor– TextPad, Notepad

• Compiler– JAVA Compiler, C++ compiler

• Language Knowledge

• Logical thinking ability


Programming with IDE

• IDE : integrated design environment

• consists of– source code editor

– compiler and/or an interpreter

– build automation tools

– Debugger

– Construction of a GUI

– Class browser

– Object inspector

– Etc.


Programming IDEs

• Eclipse

Eclipse is a multi-language software development environment

http://www.eclipse.org/

• Code:blockshttp://www.codeblocks.org/

• Netbeanshttp://netbeans.org/

• Microsoft Visual Studio

http://www.microsoft.com/visualstudio/en-us


Exercise

• Download Netbeans IDE and install it

• Download:

http://netbeans.org/

Budditha Hettige ([email protected]) 53

INTRODUCTION TO JAVA

PROGRAMMING LANGUAGE

547/11/2015 Budditha Hettige ([email protected])

Introduction to Java

• Is a programming language created by James

Gosling from Sun Microsystems in 1991

• Is a general-purpose, class-based, object-oriented

Programming language

• is intended to let application developers

“write once, run anywhere.”

• URL : http://www.oracle.com/


Java cont…

• Java programming language consists

– Java compiler:

Java compiler translates Java coding into

byte-code

– Java virtual machine(JVM)

Java virtual machine interprets this byte-code and runs the program

– Java class libraries

Java Class Library is a set of dynamically loadable libraries that Java applications can call at run time


Java Virtual Machine (JVM)

Architecture

JAVA Source File(.java)

JAVA Bite code(.class)

Java Compiler

Java Virtual Machine

Memory Manager

Byte code Verifier

Interpreter

Java API


JAVA Vs C++

58



Java Compiler

Java VM

C++ Source File(.cpp)

Executable program(.exe)

C++ Compiler

Operating system can

directly execute

JAVA VM can directly execute


Programming

• Task

– Design

– Implement

– Compile and RUN


Characteristics

Java has the following properties

• Platform independent

• Object-orientated programming language

• Strongly-typed programming language

• Interpreted and compiled language

• Automatic memory management


Platform independent

• Can Run on any Platform

– Windows

– Linux

– MaC OS

61



Java Compiler

Java VM


Object-orientated programming

language

• Object-oriented programming (OOP) is a programming paradigm that represents concepts as "objects" that have data fields (State) and methods (Behavior)

• What is an Objects?

– Object is a software bundle of related state and behavior

– Characteristics: state and behavior

– Example (Person)

• State (Name, NIC, height)

• Behavior (Speech, Sleep, eat)

– Object is an instance of a class (instance is a specific realization of any object)


http://en.wikipedia.org/wiki/Object_(computer_science)

What is a class?

• A Java class is a group of Java methods and

variables

• Example (Person)

– State (Name, NIC, height)

– Behavior (Speech, Sleep, eat)

63

class Person

{

}


Requirements for Class name

• Class name must begin with letter of the alphabet

• Contains only letters, digits, underscores or dollar

sign

• Cannot be a language reserved keywords (public,

class etc)

• Name cannot be following values (true, false or null)


Java Class name standard

• Begin with uppercase letter

• No spaces

• Emphasizes new word with an initial uppercase letter

• Example

– EmployeRecords

– Student

– FirstExample

– SampleProgram


Java Keywords


Install JAVA

• Download Java Development Kit (JDK)

– http://www.oracle.com

• RUN Installation setup

• SET PATH for the JAVA

• Test JAVA is working


http://www.oracle.com/

Simple Java Program• A class with a main Method

public class FirstProgram{

public static void main(String[] args) {

System.out.println("Hello");}

}

68

Operating System

FirstProgram

Main MethodOutput


A class without a main Methodpublic class FirstProgram{

}

Operating System Can not Execute the program

69

Operating System

FirstProgram


Your first Java program

• Open a text editor (text pad, Notepad etc.)

• Type the following sample

• Save program as “FirstProgram.java”

public class FirstProgram

{

public static void main(String[] args)

{

System.out.println("Hello World");

}

}


Compile and RUN

• Using command prompt go to the place where in

your java file

• To Compile: type javac <space><fileName>

Javac FirstProgram.java

• To Run: type java<space><fileName>

Java FirstProgram


First Java program

72

public class FirstProgram

{


{

System.out.println("Hello World");

}

}

Flow chart

Start

Display“Hello World”

End


Print Output on Command window

• Function

– System.out.println(“Some Text”);

– System.out.print(“Some Text”);

• Examplepublic class FirstProgram{

public static void main(String[] args) {

System.out.println("Hello World");}

}


Escape Sequences• A character preceded by a backslash (\) is an escape

sequence

• has special meaning to the compiler

Escape Sequence Description

\t Insert a tab in the text at this point.

\b Insert a backspace in the text at this point.

\n Insert a newline in the text at this point.

\r Insert a carriage return in the text at this point.

\f Insert a formfeed in the text at this point.

\' Insert a single quote character in the text at this point.

\" Insert a double quote character in the text at this point.

\\ Insert a backslash character in the text at this point.


ASCII art with JAVA• ASCII art is a graphic design technique that uses computers for

presentation and consists of pictures pieced together from the

95 printable (from a total of 128) characters defined by the

ASCII Standard from

75

System.out.println(" @ @ @ ");

System.out.println(" @ @ @ @ ");

System.out.println(" @ @ @ ");

System.out.println(" \\|/ ");

System.out.println(" | | | ");




System.out.println(" ( ) ");

System.out.println(" ^^^^^ ");


Exercise1. Why JAVA is Platform independent?

2. What is a class ?

3. What is JAVA Runtime Environment (JRE) ?

4. What is JAVA Class file?

5. Create a JAVA Program to display the following

output

76

EMPLOYEE DETAILS

---------------------------------------

1. Employee NO : HIT1001

2. Name : Mr. A. B. Gamage

3. Age : 30

4. Salary : 23507.50

5. Married : Y

6. Car (Y/N) : N

---------------------------------------7/11/2015 Budditha Hettige ([email protected])

Exercise

• Write a Java program to display the following

output.

[email protected]

Exercise

• Write a Java program to calculate and display total

amount of the given unit price and quantity of an

item.

[email protected]

Data Types

• Use various variables to store various information

• Variables are reserved memory locations to store

values

• When you create a variable you reserve some

space in memory

• Based on the data type of a variable, the operating

system allocates memory and decides what can be

stored in the reserved memory

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Activity

• How to change items in the two bottle


Java Data types

• The eight primitive data types supported by the Java

programming language

81Budditha Hettige ([email protected])7/11/2015

Data types


Limits of integer in java


Default values

• The default values for the above data type

84

Data Type Default Value (for fields)

byte 0

short 0

int 0

long 0L

float 0.0f

double 0.0d

char '\u0000'

String (or any object) null

boolean false

Budditha Hettige ([email protected])7/11/2015

ASCII Code for the characters


Data type selection

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Memory Allocation

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Java Variables

• Declaration

– DataType <space> VaribaleName

• Example:

– Int count;

– Int studentAge = 0;

– float GPA = 3.56


Variable name( rules)

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• Can use only letters, digits and underscore

• The first character must be a simple letter

• Case sensitive

• Cannot use keywords

• No limits on length

Local, Instance & Class Variables

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classData

localAge

age

Variables in a program

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Exercise

• Write a Java program to calculate and display total

amount of the given unit price and quantity of an

item.

• Solution

– What are the input(s)

– What are the output(s)

– How many variable are required

– What is the process

[email protected]

Answer


Constant variables

• Constants are declared like variables with

the addition of the static final keywords

static final double PI = 3.14159;

Once declared and initialized, a constant

can be used like a variable

• A constant may not be reassigned


Type Casting

• A way to convert a variable from one data type to

another data type

• Use cast operator

– (type_name) expression

– (int) float_value

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Java Memory concept

• Variable names correspond to location in the computer’s

memory

• Every variable has a name, a type, a size and a value

• A memory cell is never empty. But its initial contents may

be meaningless to your program.

• The current contents of a memory cell are destroyed

whenever new information is placed in that cell.

• Java has Total control about variables

• Programmer’s No need to think much

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Input / Output

Input from Keyboard

• Use Scanner

– import java.util.Scanner;

• Create a Scanner object to Scan input from command window

– Scanner input = new Scanner(System.in);

• Read value from keyboard

– nextInt() interger

– nextLine () String

– nextFloat() float

– nextDouble ()double

• Example

– value = input.nextInt();


Example

• Create a JAVA Program that read data from key

bard and display the result as follows

99

EMPLOYEE DETAILS

---------------------------------------

1. Employee NO : HIT1001

2. Name : Mr. A. B. Gamage

2. Age : 30

3. Salary : 23507.50

4. Married : Y

5. Car (Y/N) : N

---------------------------------------


Exercise

• Write a Java program to read two numbers from

keyboard and display the Average.

[email protected]

Solutionimport java.util.Scanner;

public class FundamantalApp

{


{

Scanner input = new Scanner(System.in);

int value1, value2;

float avg;

System.out.println("Enter value1 :");

value1 = input.nextInt();

System.out.println("Enter value1 :");

value2 = input.nextInt();

avg = (value1 + value2)/2;

System.out.println("Average is "+ avg);

} }


Examples:

• Create a java program to calculate area of a room.


Answer


Example

• Create a java program to calculate area of the

following figure

104

a

b

c


Answer


Exercise

Create a Java program to calculate and display total

amount of given unit price and quantity of the some

item.

[email protected]

Answer

[email protected]

Java Formatting

• System.out.format("%f, %1$+020.10f %n", Math.PI);


Example

Write a C++ program which will convert a weight in KG

to pounds and ounces.

( 1 Kg = 2.2046 pounds)

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Example

• Write a C++ program which will convert a Celsius

temperature into Fahrenheit

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Operators

Example

Budditha Hettige ([email protected])

What is the output of the Variable y

Java Operators• Assignment operator

– (=)

• Arithmetic operators

– ( +, -, *, /, % )

• Compound assignment

– (+=, -=, *=, /=, %=, >>=, <<=, &=, ^=, |=)

• Increment and decrement

– (++, --)

• Relational and comparison operators

– ( ==, !=, >, <, >=, <= )

• Logical operators

– ( !, &&, || )

• Conditional ternary operator

– ( ? )

• Comma operator

– ( , )


Java Operators


Binary Operators

• The binary operators take two arguments as

operands


Left Operand

RightOperand

Operator

Unary Operators

The unary operators take one arguments as operand


Operand Operator

Assignment operator (=)

• The assignment operator assigns a value to a

variable.


Arithmetic operators( +, -, *, /, % )

• The five arithmetical operations supported by C++

are


Compound assignment

(+=, -=, *=, /=, %=, >>=, <<=, &=, ^=, |=)


Combined assignment operators

• Each arithmetic operator has a corresponding

assignment operator.


Operator EffectL = Left Operator

R = Right Operator

+= Assign (L + R) to L

-= Assign (L - R) to L

*= Assign (L * R) to L

/= Assign (L / R) to L

%= Assign (L % R) to L

Example


Unary Operators

The unary operators take one arguments

- unary minus (negation)

+ unary plus

-- decrement

++ increment


Unary Operators

• The unary minus (-) makes a positive number into a

negative number and a negative number into a

positive number.

• The unary plus (+) does not change the number.

• The decrement operator (--) decrements the value of

its operand by 1.

• The increment operator (++) increments the value of

its operand by 1.


The prefix version (++x or --x)

• Comes before the operand, as in ++x

• First increments or decrements the variable by 1

and then uses the value of the variable.


meansChange xThen assign to yy = 6, x = 6.

The postfix version (x++ or x--)

• Comes after the operand, as in x++

• Uses the current value of the variable and then

increment or decrements the variable by 1.


meansAssign z to y.Then change z.y is 5, z is 6.

Relational and comparison operators

• The result of such an operation is either true or false

(i.e., a Boolean value)


Example


Logical Operators

• To combine or modify existing expressions.

! NOT

&& AND

| | OR

• Example

a > 5 && b > 5

ch == ‘y’ | | ch == ‘Y’

!valid

!(x > 5)


Conditional ternary operator ( ? )

• The conditional operator evaluates an expression,

returning one value if that expression evaluates to

true, and a different one if the expression evaluates

as false.

• Syntax is:

condition ? result1 : result2


Bitwise operators

( &, |, ^, ~, <<, >> )

Bitwise operators modify variables considering the bit

patterns that represent the values they store.


Precedence of operators


Selections

Exercise

• Write a Java program to read an examination mark

from keyboard and print “pass” if mark >= 40.


Java Selection (if Statement)

• One-Way (if) Selection

Syntaxif (expression)

{statement(s)

}

• Statement executed if value of expression true


If m>=40

PASS

Java Selection (if Statement)• Two-Way (if...else)

if (expression)

{

statement1;

}

else

{

statement2;

}

• If expression true, statement1 executed, otherwise statement2 executed


if-then-else Statement

• Syntaxif (Condition) {

statement(s)

}

else {

statement(s)

}

• Example


Exercise

Write a C++ program

to print the biggest

number of the two

given numbers


Exercise

Write a C++ program

to print the biggest

number of the three

given numbers


Exercise

• Write a C++ program to print the grade for a given

mark.


1000 40 60 75

Solution 1


Nested if and if...else Statements


• Nesting: one control statement in another

• Syntax of nested if...else statements:

if (condition1)

statement1;

else if (condition2)

statement2;

. . .

else if (condition-n)

statement-n;

else statement-z;

Answer with Nested if


Exercise

Write a Java program

to print the grade for a

given marks


DebugDebugging is a methodical process of finding and

reducing the number of bugs, or defects

Debug

• Programming errors are called bugs

• Programming errors may be

– Compiler errors

– Runtime errors

– Logical errors

• Going through the code, examining it and looking for

something wrong in the implementation (bugs) and

correcting them is called debugging


Debugging Options

• Make break points

– Right click on statement and add break point

• Add watches to see the values of the variables

– Click Debug – Debugging window - Watches


Debugging cont.…

• Start debugging (Press F8)

• Debug Commands

– F8 – Start / Continue

– F7 – Next Line

– Shift+F8 Stop


Exercise

• Write a C++ program that reads month as an integer

and print the name of the month

• Draw a flowchart to describe your solution

• Debug your code and find execution path for the

following

– Month = 1;

– Month = 12;

– Month = 6;


SwitchRun with number of possible execution paths

A switch works with the byte, short, char, and intprimitive data types

Switch

• switch structure: alternate to if...else

• Example 1:

switch(x) {

case x1: statements1;

break;

case x2: statements2;

break;

…

default: statements4;

break;

}


Exercise 5.6

• Write a C++ program that reads month as an integer

and print the name of a month.

(Use Switch)


Exercise 5.7

• Draw a flowchart to above program


Exercise

• Write a Java program that reads day as an integer (1-7)and print the name

– Use only if-else statement and implement your solution

– Use switch statement and implement your solution

• Draw flowcharts to above two programs

• Compare performance of the two methods (if and Switch)

– Use debug and find the execution path


Exercise

• Write a JAVA program that reads day as an integer

(1-7)and print the name


Exercise

• Write a Java program to display a given date as the

following formats.

Your program should read date as the three inputs

(day, month and year) and generates the output

forms.

– Option 1: 21.05.2001

– Option 2: 21.05.01

– Option 3: 21 st May 2001


Answer


Answer

1. Print a day

2. Print (st/nd/rd/th)

3. Print month

4. Print year


Exercise

• Write a Java program to print the bill for an item bought by a customer from a shop.

– The program should ask unit price and quantity of an item and calculate the total cost

– If item quantity greater than 10 give one item free

– Add 3.5 % discount for the total if total cost grater than 2500.

– The bill should contain all the above information and amount of money tendered and the correct amount of change.


Exercise

• Write a JAVA program to find the roots of the quadratic equation 𝒂𝒙𝟐 + 𝒃𝒙 + 𝒄 = 𝟎 where xrepresents a variable or an unknown, and a, b, and c are constants.

• Hint: The following equation shows the solutions of the quadratic equation

• Read more on quadratic equation: http://en.wikipedia.org/wiki/Quadratic_equation


LoopsLoops have as purpose to repeat a

statement a certain number of times or while a condition is fulfilled.

Repetitions: Loops

• A loop is a sequence of instruction s that is

continually repeated until a certain condition is

reached.

• The statement may be repeated

– For a specific number of items

– For an indeterminate number of times, depending

on the truth or falsity of some condition.


http://searchcio-midmarket.techtarget.com/definition/instruction

Loops

• C++ provides three types of loops

– for loops (1- n times)

• Repeat a section of code known number of times

– while loops (0 – more times)

• Loop is used to repeat a specific block of code an unknown number of times

– do while loops (1 – more times)

• A do while loop is a control flow statement that executes a block of code at least once, and then repeatedly executes the block


Repeat some work

• Do some repeated work

– Initialization (Start number)

– Condition (do repeat action until satisfy some condition)

– Update (Next Value)

• Example

– Initialization Start with 1

– Condition Count up to 50

– Update Count 1 by 1


For Loop• Syntax

for (initialization; condition; update)

{

statement(s)

}

• ExampleInitialization

Update

Condition


Exercise

Write a Java program to find the

factorial of a given number

Example:


Nested for Loops

• A loop can be nested inside of another loop

• Syntaxfor ( init; condition; increment )

{

for ( init; condition; increment )

{

statement(s);

}

statement(s);

}


Exercise

• Write a Java program to display the following

Multiplication table


Exercise

1. Write a Java program to print the

following figure

a) * b) 1

** 12

*** 123

**** 1234

***** 12345


While Loop

• Allows the repetition of a statement based on the

truth value of a condition

• Can run 0 to infinite times


While Loop

• Syntax

while (Condition)

{

statement(s)

}

• ExampleInitialization


Condition

Update

Exercise


• Write a Java

program to find

the factorial of a

given number

(Use While loop)

Exercise

• Write a Java program

to accept numbers

until the user enters a

999 and output the

sum of the given

numbers


Exercise

Create a java program to identify the given number is Palindrome number or not.

– Read number as an integer

– Find the number is Palindrome or not

– Print the results

Hint:A palindromic number or numeral palindrome is a number that remains the same when its digits are reversed. Like 16461


Answers


Do-while Loop

• do…while loop also depends on a condition, but

unlike while loop, its condition is evaluated at the

bottom of the loop, after the body has already

executed.


Do-while Loop

• Syntaxdo

{

statement(s)

}

while (condition);

Example


Update

Condition

Initialization

Loops comparison

For while do-while


Exercise

Accept numbers until the

user enters a 999 and

output the average of the

given numbers


Exercise

• Using do-while loop, create a java program to

display the selected option in the following menu;

[1] Enter data

[2] Print data

[3] Exit the program

do-while

Switch


Answer


Exercise

Write a Java program to read N number of integers

and find the total and average.

• N is an input 1, 2, 3….. N

• Use for, while and do-while loops

• Draw 3 flow chart for the above 3 programs


Exercise

Write a Java program to compute the gross pay for an

employee. An employee is paid at hourly rate for the

first 40 hours worked in a week. Any hours worked in

excess of 40 hours are paid at the overtime rate of one

and half times that. Your program should print the pay

sheets of all the employees.


Functions

and

Methods

Exercise

• Create a Java program to display the following

wordArt.(MAM)


Functions

• Functions are a basic building block for writing Java programs.

• Breaking a program up into separate functions, each of which performs a particular task, makes it easier to develop and debug a program

• Solution for code reuse

• Functions allow for breaking down the program into discrete units

• Use to modular Programing


Methods

• Is a group of statements that is executed when it

is called from some point of the program.

• Types

– Built-in: Build-in methods are part of the compiler

package, such as

• System.out.println( )

– User-defined: User-defined methods are created by you

• Format

Return type MethodName (Argument..)

{ }


Method Example 1

187

printMeMain

PrintMe


Method Example 2

188

printMe

Main

PrintMe


Method Example 3


Scope of a variable

190

1 2

3

4


Example

• Create a Java Programs to do to the following

1. Read Celsius temperature and calculate the

Fahrenheit temperature

Celsius to Fahrenheit: (°C × 9/5) + 32 = °F

Hint:

– A Method to read data from keyboard

– A Method to Calculate data

– A Method to Print Data


Methods


Methods


Complete Program

194

getValue

Claculate

printData

Main

getValue

calculate

printData


Top-Down Design

195

Main

getValue claculate printData


Bottom-up Design

196

Main

getValue claculate printData


Modular Design


Main

getValue

claculate

printData

Example

• Create a JAVA Program that reads 3 integer values

from keyboard and print total and average values.

• Hint:

– Draw a top down design

– Implement your solution


Arrays

What is Array

• An array, is a data structure consisting of a

collection of elements

• Each identified by at least one array index or key

• simplest type of data structure is a linear array, also

called one-dimensional array


Arrays

• An array is a container object that holds a fixed

number of values of a single type


Arrays contd.

• Declares an array of integers

– int[] anArray;

• Allocates memory for 10 integers

– anArray = new int[10];

• Initialize first element

– anArray[0] = 100;

• Display Values

– System.out.println(“E0”+ anArray[0]);


Example

• Write a Java program to store marks of 10 students

and print average mark ? Output of your program is

as follows

Student Marks

1 67

2 89

...

---------------------

Average 45.56

=====================

Budditha Hettige ([email protected]) 2037/11/2015

Exercise

• Write a Java program that read 10 integer marks

(Range 0 to 100) form keyboard and print the result

sheet as shown below.


Write a Java program that read 10 integer marks (Range 0 to 100) form keyboard and print the result sheet as shown below.

ICT 126 2.0 Introduction to Computer Programming

------------------------------------------------

####### RESULT SHEET ######

------------------------------------------------

Index NO Marks

================================================

1 56

2 79

3 45

1. 23

...

Find elements

• Find the largest and small mark of the above marks

array


Example (several arrays)

• Create 2 Arrays to store Student name and GPA

values of the 25 students in a class

• Enter all values and print results in the following

format

Student summary

---------------------

Saman Kumara 2.56

Ruwan Silva 1.94


Multiple Arrays

• Write a C++ program to store 10 student information

in class with considering name, age, height. Your

program should read 10 students information from

keyboard and display results as given below

name age height

--------------------------

saman 14 5.7

kamal 12 5.1


Console

Applications

Console Application

• Runs only console screen(Command window)

• NO GUI

• Use Low resources

• Use only key board action


Example


Example


user interface

Example


Main Menu

Example 3 (contd.)


Action

Example 3 (contd.)


Summary

Example 4

• Create Java Application to calculate total price for

the sold items.

– Your program should run as a menu driven

application

– User can add items (any ) and print total, number

of items and discount

– User can total sales price for a day

– This program should run until user exit


Run Application Without Netbeans


RUN Application


Model Questions


END.


Documents

Fundamentals of Programming - · PDF fileFundamentals of Programming Course Structure ... • Linker—combines the compiler- ... runs the program –Java class libraries