Software Development Techniques - Topic 01

Topic 1 : Introduction to Module

Er. Pradip Kharbuja

What will you learn?

1. Software Development Concept

2. Pseudo code

3. Flowchart

4. Algorithm

5. Data Representation

6. Desk Checking

Compiled By: Er. Pradip Kharbuja

What will you learn? (Contd.)

7. Iteration

8. Selection

9. Functions

10.Array

11.Objects & Classes

12.Data Structures

13.Testing and Debugging


Terminologies

1. Input

2. Output

3. Pseudo Code

4. Flowchart

5. Algorithm


Terminologies

1. Input

The process of bringing information into a computer program

This may be from the user, or from another source such as a file

2. Output

Displaying or storing information outside the computer program

To the screen, or perhaps to another location or to store in file.


Terminologies

3. Algorithm

A method or logic or some calculations or step-by-step procedure to solve the given problem.

An algorithm is procedure consisting of a finite set of unambiguous rules (instructions) which specify a finite sequence of operations that provides the solution to a problem.


Terminologies

4. Pseudo Code

It’s not real programming code, but it helps to write the real code.

Pseudo code is a way to describe the algorithm in order to transform the algorithm into real source code.

We write it before we write computer code because it allows us to ensure that the logic is correct.


Terminologies

5. Flowchart

• A flowchart is a type of diagram that represents an algorithm or process.

• The diagrammatic representation illustrates a solution to a given

problem.


Symbols used in Flowchart


Terminologies

1. Assembler

2. Compiler

3. Interpreter

4. Compilation

5. Execution

6. High Level Language

7. Low Level Language


Write down the following words.

• Software Development Techniques


You wrote…. How?

Did I tell you to write with pen?

Did I tell you to write on copy?

Also did I tell to open your pen’s cap before you write?

But you did, because you are intelligent. But computer is stupid.


Computer Programming

• Computers are very stupid.

• All they know how to do is add.

• They don’t know how to deal with ambiguity.

• Pick up the thing and put it on the other thing.

• They are extremely obedient.

• And that’s not always a good thing.

• They can’t fill in the blanks.

• You need to tell them everything.

• This makes giving instructions to a computer very tricky.Compiled By: Er. Pradip Kharbuja

Computer Programming (Contd.)

• At its simplest, you can think of a computer program as a list of sequential instructions.

• Buying a copy :

Go out of the home

Go to the stationery shop

Ask for copy

Select copy

Pay for copy

Take copy home



• Computers don’t understand English.

• They only know 1 and 0.

• We usually don’t speak 1 and 0.

• Although, people did once in order to program computers.

• It is known Machine Level Programming Language or Low Level Programming Language



• To simplify the task of giving instructions to a computer, programming languages were created.

• We write things in a language that’s semi-understandable to us.

• The collection of instructions that are to be given to a computer are known as code.

• The rules that govern how a computer program must be put together are called its syntax.



• So... what is a computer program?

• It’s the collection of instructions and information that work together to make the computer do something.

• Programs are made up of algorithms and data.

• An algorithm is a fixed set of operations that is performed (usually) on data.

• Data are the raw facts that the computer program holds.


The History of Software Development

• In the beginning, computer programs were written as 1s and 0s.

• This programming language was known as machine code or Machine Level Programming Language or Low Level Programming Language.

• Every different kind of computer had its own machine code.

• So, machine code were machine dependent.



• Machine code was difficult for humans to work with.

Too much to remember

Too hard to see mistakes

Too difficult to change programs once they had been written

Too low level for people to write well



• A new kind of programming language, called assembly language, was introduced to make writing machine code easier.

• It is also low level programming language.

• Assembly language used (almost) human readable words to represent collections of 1s and 0s.

• Machine code might need you to write 10110000 01100001

• Assembly language meant all you had to write was MOV AL, 61h



• The computer itself doesn't understand assembly language.

• It is needed to be converted into machine code.

• This was done through a process called assembling and done by Assembler.

• Every computer has its own version of assembler.

• If you learned how to write code on one computer, you needed to learn a new version of assembler to write code on another – Machine Dependent.



• Assembly language still wasn’t easy to write program code with.

• Disadvantages of Low level Programming Language

1. Very hard to read or learn.

2. Harder to modify and maintain.

3. Machine dependent or not portable across different devices.



High Level Programming Language

• easier to read, write, and maintain

• generally machine independent

• makes the process of developing a program simpler and more understandable

• Example : C, Ada, BASIC, COBOL, C++, FORTRAN, LISP, Pascal, Java, PHP, C#.NET



High Level Programming Language

• The most popular of these was a language called C. It’s still used even today.

• C code was human readable and worked (mostly) across lots of different computers.

• C => C++ => Java


Terminologies

• A compiler is a computer program that transforms source code written in a high level programming language into machine code.

• This process is called Compilation.

• You need to compile only once unless any source code is modified

• Once a program has been compiled, it is now ready to execute.

• Execution is the process of loading the program into the computer’s memory.

• This is also known as running a program.Compiled By: Er. Pradip Kharbuja

Assembling and Execution

• A. L. Program = Assembly Level Program


A. L. Program A. L. Program A. L. Program

Machine Code Machine Code Machine Code

System 1 System 2 System 3

Assembling

Execution

Compilation and Execution


Machine Code Machine Code Machine Code

System 1 System 2 System 3

Compilation

Execution

High Level Program Code

How to Write A Program

• First, decide what information you are going to need to store.

This is data representation

• Decide how you are going to get that information.

This is known as input

• Decide how you are going to manipulate that information.

This is your algorithm.

• Decide how you are going to display that information.

This is known as output.Compiled By: Er. Pradip Kharbuja

Task : Print Hello World

1. Problem Identifying

2. Requirement Analysis

3. Program Design

a. Pseudo Code

b. Flowchart

c. Source Code

4. Output



• Displaying “Hello World” Text



Output

Hello World


3. Program Designa. Pseudo Code

• Start

• Output “Hello World”

• Stop


3. Program Design b. Flowchart

Stop

Start

Output

"Hello World"


3. Program Design c. Source Code

• - We will do it in programming language : Java / C / C++ / Visual Basic


4. Output

• - Output must be shown at 3 times

a. Negative Input

b. Normal Input

c. High Input

- Current Pseudo Code Output

a. Hello World

b. Hello World

c. Hello World


Task #1

Input your name and display.

• You must display text “Enter your name : ”

• You must display text “Your name is : ”


What you have to do?



3. Program Design

a. Pseudo Code

b. Flowchart

c. Source Code

4. Output


Task #1


• Take user input with displaying text

• Display result with certain text


Input Output

Enter your name : n1 Your name is : n1


Task #1

3. Program Design

a. Pseudo Code

Start

Output “Enter your name : “

Input n1

Output “Your name is : ”

Output n1

Stop


Task #1

3. Program Design

b. Flowchart

Stop

Start

Output

“Enter your name : "

Input n1

Output n1


Output

“Your name Is “

Task #1

4. Output

Output 1

• Enter your name : David

• Your name is : David

Output 2

• Enter your name : 124

• Your name is : 124

Output 3

• Enter your name :

• Your name is :Compiled By: Er. Pradip Kharbuja

Task #2

Now take 2 numbers and display them.• You must display text

Enter 1st number :

Enter 2nd number :

The 1st number :

The 2nd number :


Task #3

Take following inputs and display them:

1. First Name

2. Last Name

3. Address

4. Phone Number

5. Age


Task #4

Take 2 inputs from user and add them.


Task #4


• Take 2 user inputs

• Sum them

• Display the result


Input Process Output

n1

n2

n3 = n1 + n2 n3


Task #4

3. Program Design

a. Pseudo Code

Start

Input n1

Input n2

n3 = n1 + n2

Output “The sum is : ” + n3

Stop


Task #4

3. Program Design

b. Flowchart

Stop

Start

Input n1

Output

“The sum is : “ + n3

Input n2

n3 = n1 + n2


Task #4

4. Output

Output 1 (with Negative Input)

-5

-20

The sum is -25

Output 2 (with Normal Input)

10

20

The sum is 30

Output 3 (with High Input)

3000

4000

The sum is 7000


Assignment #1

1. Program demonstrating sum, subtraction, multiplication, division

2. Averaging five ages

3. Find the area of rectangle

4. Find the area of circle

Assignment Deadline: 18th August, 2014 before 2:00 PM


End of Topic - 1


Software Development Techniques - Topic 01

Technology

Transcript of Software Development Techniques - Topic 01