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1.1 Introduction concepts

1.0 Introduction To Programming

1.1.1 Term

programme

programmerProgramming

language

Program: A set of step-by-step instructions that directs a computer to

perform a specific task and to produce the required results.

Programming:

Programming is a process of designing/ creating a program.

Programmer:

Programmer is a person who writes the program.

c) A programming language

is set of instructions that can be used to

construct a program. A notation for

writing programs, which are specifications

of a computation or algorithm.

is a language designed to describe a set of

consecutive actions to be executed by a

computer. A programming language is

therefore a practical way for us (humans)

to give instructions to a computer.

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1.1.2 Various types of Programming

Languages There are three basic types of

programming languages.

1.1.3 (i) Machine language

The lowest-level programming language

Machine languages are the only languages understood by computers.

While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers.

Expressed in binary form, an instruction might be 0111010110110011. Very difficult to use. Lowest level of computer languages.

For example, a program written in Apple PC cannot be run in IBM PC

ii) Assembly language

Second level of language.An assembler

translates assembly language.

It was developed to replace "0" and "1" used in Machine Language.

Machine languages consist entirely of numbers and are almost impossible for humans to read and write.Takes a long time to write programs

English-like abbreviations representing

elementary computer

operations (translated via assemblers)

Example: C++, C , FORTH

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iii) High-level language

Instruction is written as a series of English-like words.

Translator (Compiler/Interpreter) is needed to translate high level language to machine language.

It is Machine-Independent. The program can be written and executed on any computer.

E.g. Fortran, COBOL, SQL, PROLOG, C

1.1.4 Structured Programming

Languages

Definition of Structured Programming

Structured programming can be defined as a Software application programming technique that follows a top down design approach with block oriented structures.

It support loop such as while, do-while and for.

Structured programming

The most popular structured programming languages include C,C++, Ada, and Pascal.

Codes similar to everyday English

Use mathematical notations

Example: if (x < 10) {

printf(“too low, ry again\n”);

Scanf(“%d”,&x);

}

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b) Modular programming

Programming paradigm based on data types.

An object stores a data type value; variable name refers to object.

A programming style that brakes down program functions into modules, each of which accomplishes one function and contains all the source code and variables needed to accomplish that function.

Modular programming is a solution to the problem of very large programs that are difficult to debug and maintain. By segmenting the program into modules that perform clearly defined functions, you can determine the source of program erros more easly.

c. Object-Oriented Programming

Languages

is about relation between the data and the code operating on the data (or data operating on the code).

is a programming paradigm that uses "objects" –data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction, encapsulation, modularity, polymorphism, and inheritance. Many modern programming languages now support OOP

is one the newest and most powerful paradigms. In object- oriented programs, the designer specifies both the data structures and the types of operations that can be applied to those data structures.

This pairing of a piece of data with the operations that can be performed on it is known as an object. A program thus becomes a collection of cooperating objects, rather than a list of instructions.

Objects can store state information and interact with other objects, but generally each object has a distinct, limited role.

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An object stores a data type value;

variable name refers to object.

Object-oriented programming (OOP) is a

programming paradigm based on data

types.

The most popular object-oriented

programming languages include Java, Visual

Basic, C#, C++, and Python.

Object-orientated programming

languages, such as SmallTalk and

HyperTalk, incorporate modular

programming principles

1.1.5 Comparison between the

following types of programming:

a) Structured programing

The main advantage for structured

programing is that it make input easy, and

also it is better to use because it does not

merges the data we stored in strings and

variables, sometime it happens that we get

merged data if we don't use structured data.

And it also make easy to manage variables.

Structured programming is as

follows:

--Program startvarvarvar

function { ... }function { ... }function { ... }

main { ... }--- Program End

You have units of code, which operate on variables, and are called in reference to those variables, to follow a structure acting on those variables.

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b) Modular programming

-A detailed process of problem solving

-Break a large problem into several

smaller

Sub-sections are solved separately by

observing that all these small modules to

solve the whole problem of the origin

Modular Programming - Need

and Approach

Typical industry programming projects

consist of thousands of lines of code or

more

Analogous approaches: manufacturing a

spacecraft, or a car Manufacture individual

components, test separately

Assemble into larger components,

integrate and test

Modular Programming -

Process

Advantages of Modular

Programming

Manageable: Reduce problem to smaller, simpler, humanly comprehensible problems

Divisible: Modules can be assigned to different teams/programmers

Enables parallel work, reducing program development time

Facilitates programming, debugging, testing, maintenance

Portable: Individual modules can be modified to run on other platforms

• Re-usable: Modules can be re-used within a program and acrossprograms

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An Example of Code that Doesn't Use

Modular Programming

A simple example of repeated code can be seen in:

PI = 3.14159265358979

R = 1

C = 2 * PI * R

A = PI * R * R

wscript.echo "Radius " & R & " Circumference " & C & " Area " & A

R = 2

C = 2 * PI * R

A = PI * R * R

wscript.echo "Radius " & R & " Circumference " & C & " Area " & A

R = 3

C = 2 * PI * R

A = PI * R * R

wscript.echo "Radius " & R & " Circumference " & C & " Area " & A

R = 4

C = 2 * PI * R

A = PI * R * R

wscript.echo "Radius " & R & " Circumference " & C & " Area " & A

Here the same functionality is repeated but does works (as can be seen in f igure 1). However, the programmer can work more ef f iciently by using modular programming.

A Simple Example of Modular

ProgrammingThe aim of the programmer is now to ensure that code is reused as much as possible. They do this by identifying the code that can be place

separate functions and subroutines:

PI = 3.14159265358979

function circumference (R)

circumference = 2 * PI * R

end Function

function area (R)

area = PI * R * R

end function

sub print_details (R)

C = circumference (R)

A = area (R)

wscript.echo "Radius " & R & " Circumference " & C & " Area " & A

end sub

print_details 1

print_details 2

print_details 3

print_details 4

The output is the same as before (as can be seen in figure 2), but this time the chance of the operation of the script being altered due to a typing error is greatly reduced, and if there is an error then the task of correcting it is made much simpler. The programmer can also use the functionality throughout their application without worrying about having to rewrite the code, thereby improving the e ff iciency of both the code and their time.

c)Object oriented

- fourth-generation language is object

oriented.

- Programmers will more tend to think of

the objects involved

the problem and the relationships

between objects.

-Examples of programming languages are

C + + Java

Why Object Oriented Language?

Reusability-Cepatkan project

- Improve the quality of

- Easily adjusted

- Flexible

- Easy maintenance

- Reduce the risk for complex projects

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c) Object oriented

is as follows:

--- Program Startobject {varvarfunction { ... }function { ... }function { ... }}

varvar

function { ... }main { ... }--- Program end

Variables can be objects, which have their

own data and functions. Think like C and

structures, except structures can have

functions "in them" which operate

specificly on their own data.

Example 1: Object-oriented

Problem Solving Approach

Step 1: Problem Identification - Compute

the sum of two numbers and print out

the result.

Step 2: Object Identification

- Identify objects needed to solve the

problem.

Num1 - first number (object).

Num2 - second number (object).

Sum - result of the addition of the two

numbers (object).

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Step 3: Message Identification

- Messages needed to send to objects.

+ aNum - This is the message sent to the receiver object with an parameter aNum. The result of this message is the value (a numeric object) of the total sum of the receiver object and aNum. print - a message that displays the value of the receiver object.

Step 4: Object-message sequences - Following is the object-message sequence to solve the problem.

(Num1 + Num2)print The message + with a parameter Num2 (an object), is sent to the object Num1.

The result of this is an object (Num1 + Num2), which is sent the message print. The parentheses are included to avoid any ambiguity as to which message should be activated first.

Note: The sequence of Smalltalk evaluation

is from left to right unless is specified by

parentheses ( ). For example:

2 + 3 * 4 is 20

while

2 +(3 * 4) is 14

1.2.1 Stages of Problem Solving

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The steps in programming:

1-Definitions and identify problems- Identify and understand the problems to

be solvedi. Read the questions and identify and

understand the requirements of the questionii. For the analysis to determine the

problem with three main areas:* Input required* OUTPUT issued* PROCESS determine the formula

to get the output from a given input

1.2.2 Elements of problem analysis

PROCESS

2 - Planning variables

variable is a reference to a memory

location

Variables with a specific type of data to

determine the memory size provided

All variables must be used in the program

prior diishtiharkan

3. Design a flow chart (design

software) Better known as the process of

designing algorithms

algorithm - list of measures to solve

problems

Created before the actual program coding

to make sure the solution method

correct the problem that is use

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There are two ways to write the

algorithm:

i. Pseudo code

-Steps problem solving

-Written to spoken language daily

Pseudo code

Example: Changing a bulb is burned

Start

Removing the bulb is burned

Replace with new bulb

End

Is it sufficient for the

implementation of the computer?

Example: Changing a bulb is burned (details)

StartPlace the ladder in the position of the bulb burnsChoose a suitable lampTake the stairs up to the light bulb that burnsTurn the bulb counterclockwise and take out the bulbFit the new bulb in place properTurn the bulb clockwiseDown the stairsPlace the back stairsEnd

Contoh:Mengira harga

bayarbagi buku

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4-Writing program

- Represents the implementation phase in which the code was written and typed into the computer-The program should follow the syntax correctly written on the appropriate programming language- Some programming languages: BASIC, COBOL, FORTRAN, C + +, Visual BASIC and other.

Problems ---- Pseudo Code /flow chart -----program

5-Testing & debugging program

-The program that has been built to test / run (run) to ensureoutput produced is correct and meet the needs of users- Menyahsilap (debugging) --- the program is tested with real data-There is a possibility of erroneous output (error) could result from a

program written

The types of programming errors

i) Syntax Error / encoding

when programmers fail to follow the rules governing how the instruction should be written.

Example: wrong spelling of the WRITE command. The computer will print a diagnostic message.

After all syntax errors corrected or removed compiler can understand and translate the program.

ii) Logic errors

error occurred from instruction sequences that are not correct.

It might be the error in logic programming.

Instruction means may be in conflict.

Example: the programmer should write direction READ but it write WRITE

iii. Time Error

Due to data entry is not in accordance

with the instructions written in

programming

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6-Documentation Program

If the output properly certified and meet

consumer needs

- at this stage is to prepare a report for

reference and for the updates in the

future

- Facilitate the programmer to understand

the design and programmable logic

The documentation includes:

Type of problem or the specific requirements

of the appropriate

Description of inputs, outputs, constraints and

formulas for problem

A tool used logic---- flow chart or pseudo

code

Example output of the program was

implemented (executed) using the test data

The steps or guidelines for using the program

1.2.4 Determine input, process and

output for a given problem

Understand, identify and define problems.

Determine the input requirements,

process and output (IPO)

Provide IPO

Problem analysisProblem 1

Create a program that will accept three numbers as input from the user. Find the average number and the third show -the three numbers together with the average value.

Analysis of problemsInput - 3 numbersProcess - 1. Add 3 numbers

2. 3 Divide the total number to 3Output - 3 and the average number

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answers Problem 2

Given the value of x = 10 and the value of

a = 12, find the equation of state revenue

under

y = 2x + a -6

Problem analysis

1) Input:

the value of x = 10

and the value of a = 12

2) the formula / process:

y = 2x + a - 6

3) output:

the value of y

1.2.5 DESIGN TOOL

It is a framework or flow that shows the

steps in problem solving.

Methods to design a program:

Flowchart

Pseudocode

IPO Chart(input-process-output

chart)

Structure Chart

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a) Flowchart

A graphical representation of data,

information and workflow using certain

symbols that are connected to flow lines

to describe the instructions done in

problem solving.

It shows the flow of the process from

the start to the end of the problem

solving

Explanation of basic

flowchart symbol:

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Cont…Explanation of basic

flowchart symbol:

There are few additional symbols of flowchart

used in a complicated program: GOSUB and

RETURN. It’s usually used in a big program.

Example Flowchart:

Flowchart to calculate the total of fine for late

returning of library books.

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b)Pseudocode

Steps in problem solving that is written half in programming code and half in human language.

For example, some part uses C language code and some part uses Malay or English language.

Advantages:i. Easily understood.

ii. Easily maintained.

iii. The codes are changeable.

Disadvantages:

Cannot be executed in the computer.

Example:

START

Total=0, Average=0

Input a, b, c

Total = a + b + c

Average = Total / 3

Output a, b, c

Output Average

END

c)IPO Chart (Input Process

Output)Chart IPO (input output processing)

Compiling information available in the Detailed get in shape with a display input,

processing and output

Problem 1

Uncle Ahmad wants to buy 5 cans of paint

to paint his house. The price for a can of

paint is RM 25.50. Calculate the price to

be paid for 5 cans of paint to buy.

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analysis of the problem:

1) input:

Number of cans of paint purchased, the

price of a can of paint

2) The formula / process:

5 cans of paint price = price x number of

cans

3) output:

prices for purchased 5 cans of paint

Problem 2

A lecturer to determine the grade a

student based on the marks obtained by

students in the special examination. If you

score between 85 and 100, grade A if the

student is not the student will receive a

grade of B. What grades will be earned by

the student if the score is 89?

1) input:

marks obtained

2) The formula / process:

If you score 85-100, is a grade A

If the contrary is a B grade

3) Output:

grade obtained

Problem:

A photostat shops charge 5 cents

for each page copied. Design

solutions to calculate the fee should

imposed if a number of pages that have

been

diphotostat.

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definition and identify problems

plan using the variable

Writing pseudo code

Design a flow chart (design software)

Example 1:

Problem: To calculate the amount of water bill

Example 2:

Problem: To calculate area of a circleExample : Calculate the Salary of

Employee

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d)Structure Charts Structure chart is an additional method in

preparing programs that has many sub modules.

It consists rectangular boxes, which represents all the sub modules in a program and is connected by arrows.

It illustrates the top-down design of a program and is also known as hierarchical chart because its components are in hierarchical form.

The advantage is that it is easy to be drawn and to be changed.