FP101

WEEK 5

CLO 1

Explain the basic computer and programming fundamentals with appropriate examples of language and technology

-Specify the Problem

-Analyze the problem

-Design the algorithm to solve the problem

-Implement the algorithm

-Test and verify the completed program

-Maintain and update the program

-Documentation

Programming Life Cycle

• There are 7 phases in programming Life Cycle:

Specify the Problem

Problem Statement

Compute and display the total cost apples given the number of kilograms of apples purchased and the cost per kilogram of apples.

Compute and display the total price apples given the weight in kilograms of apples purchased and the priceper kilogram of apples.

Specify the Problem

• The first step in solving any problem is to understand it.

• Read the requirements statement carefully.• State the problem clearly and unambiguously.• Gain clear understanding of what is required

for its solution.

Specify the Problem

• In problem requirement phase you may ask some question like

a. What to compute?

b. What unit do they use?

c. Is it only for the apple or other fruit?

or any question for gaining understanding of what is required.

Analyze the problem

• Identify the problem inputs you have to work with and also the problems outputs (results) desired.

• Check any additional requirements or constraints on the solution.

• Determine the required format of the results to be displayed.

• Develop a list of variables.

Analyze the problem

• To analyze the problem you may summarize the information contained in it and find out the problem input and output.Problem Inputsa. weight in kilogramb. price per kilogram ( in RM per kg)Problem Outputa. Total price (in RM)

Analyze the problem

• Develop a list of formulas that specify relationships between the inputs and the outputs:

Total price = price per kilogram x weight in kilogram .

Analyze the problem

• Find a list of solution alternatives

Ex:

1. Define price per kilogram as constant and weight in kilogram as input value

2. Define price per kilogram and weight in kilogram as input values

Analyze the problem

• All the information gained from analyzing the problem can be put into problem Analysis chart (PAC)

Given Data Required Results

Weight in kilogramPrice per kilogram

Total price

Processing Required Solution Alternatives

Total price = price per kilogram x weight in kilogram

1. Define price per kilogram as constant and weight in kilogram as input value

*2. Define price per kilogram and weight in kilogram as input values

Design the algorithm to solve the problem

• Once you fully understand the problem and have clarified any questions you have, you need to develop your solution.

• Algorithm is a set of instructions for the computer

• Setting up the algorithms is probably the hardest part of problem solving on the computer

Design the algorithm to solve the problem

• The instructions cannot assume anything, cannot skip steps, must be executable one step at a time and must be complete

• Example of algorithm:

1. Input the weight in kilograms of apples purchased and the price per kilogram of apples

2. Calculate total price apples using the formula:

Total price = price per kilogram x weight in kilogram

3. Print Total Price

Design the algorithm to solve the problem

• Tools which can be used to help you in this task:

a) Structure Chart

b) IPO chart

c) flowchart

d) pseudocode

Design the algorithm to solve the problem

a) Structure Chart• Depict the overall organization of a program, show

how program segment or modules are defined and how they relate to one another. • The module in the upper row serve as control

functions directing the program to process modules under them as appropriate. • It follows a top-down design philosophy.

Design the algorithm to solve the problem

a) Example : Structure ChartTOTAL PRICE CONTROL

MODULE0000

READ1000

CALC2000

PRINT3000

Design the algorithm to solve the problem

b) IPO (Input-Processing-Output) chart

- shows in more detail what data items are

input, what processing takes place on that

data and what information will be the end

result, the output

Design the algorithm to solve the problem

b) Example : IPO (Input-Processing-Output) chart

Input processing Module reference number

Output

Weight in kilogramPrice per kilogram

1. Enter Weight in kilogram

2. Enter Price per kilogram

3. Calculate Total price

4. Print Total price5. End

1000

1000

2000

30000000

Total price

Design the algorithm to solve the problem

c) flowchart

- graphic representations of the algorithm

- shows the flow of processing from the beginning to the end of a solution

- each block in a flowchart represents one

instruction from an algorithm

- flow lines indicate the direction of the data

flow

Design the algorithm to solve the problem

start

Input WeightInKg, PricePerKg

TotalPrice = WeightInKg * PricePerKg

Print TotalPrice

end

c) Example : flow chart

Design the algorithm to solve the problem

d) pseudo code• Uses English like statements in place of the

flowchart graphical symbols. • It is easier to code a program from it than from

flowchart. • It is not tied to any programming language.• It is easy to modify but not graphical, difficult to use

for logically complex problems, and slower to create.

Design the algorithm to solve the problem

d) Example : pseudo code

START

Input WeightInKg, PricePerKg

TotalPrice = WeightInKg * PricePerKg

Print TotalPrice

END

Implement the algorithm

• This step involves writing the algorithm as a program.

• By using flow chart as the guideline, start writing a program from the top of flow chart and work your way to the bottom.

Implement the algorithm

• Example of program code in C++#include <iostream.h>

int main()

{

float WeightInKg, PricePerKg, TotalPrice;

cout<<“ Enter weigh in Kg: “;

cin>> WeightInKg;

cout<<“ Enter price per kg: “;

cin>> PricePerKg;

TotalPrice= WeightInKg * PricePerKg;

cout<<“ Price of apples : RM “<<TotalPrice;

return 0;

}

Test and verify the completed program

• After writing the program, you must test it. • Program testing can be a very tedious and

time consuming.• Run the program several times using the

different sets of data.• Make sure that it works correctly for every

situation provided in the algorithm.• Example: Blackbox Testing or Whitebox

testing.

Test and verify the completed program

• Blackbox testing gets its name from the concept of testing the program without knowing what is inside- without knowing how its works. By a user.

• Whitebox testing assumes that the tester knows everything about the program. It is a programmer’s responsibility.

Test and verify the completed program

• Errors are so common that they have a special name (BUGS). Bugs must be identified and corrected.

• The process of identifying and correcting bugs is known as debugging.

• When the compiler detects an error, the computer will display an error message, which indicates that you have made a mistake and what the cause of the error might be.

Test and verify the completed program

• Types of error in programming- Syntax Error / Compiler Error

- Run-Time Error

- Logical Error

Test and verify the completed program

• Syntax Error (Compilation Error)– An error in the format of a statement in a

computer program that violates the rules of the programming language employed. – A program will not be executed until all syntax

errors are corrected – Error can be traced at the event of compilation

Test and verify the completed program

• Run –time error– Are detected by the computer and are displayed

during execution of a program.– A run-time error occurs when the program directs

the computer to perform an illegal operation, such as dividing a number by zero or

Test and verify the completed program

• Logical Error– The hardest errors to find and fix. – A logic error means although the language syntax

was used correctly, there was a misunderstanding: if you want a, where b=c+a and you give a = b-a instead of a = b-c, then you will get the wrong answer, but have used the correct language syntax.

Maintain and Update the program

• Maintenance and update are the modification of a software product after delivery to correct faults, to improve performance or other attributes, or to adapt the product to a modified environment.

Maintain and Update the program

• Types of maintenance

a) Corrective maintenance

- Reactive modification of a software product performed after delivery to correct discovered problems. It deals with fixing bugs in the code.

b) Adaptive maintenance

-Modification of a software product performed after delivery to keep a software product usable in a changed or changing environment. It deals with adapting the software to new environments.

Maintain and Update the program

• Types of maintenance

a) Perfective maintenance

-Modification of a software product after delivery to improve performance or maintainability. It deals with updating the software according to changes in user requirements.

b) Preventive maintenance

-Modification of a software product after delivery to detect and correct latent faults in the software product before they become

effective faults. It deals with updating documentation and making the software more maintainable.

Documentation

• documentation should be concise so the person who reads it doesn't have to spend too much time to find what he or she is looking for.

• There are two types of documentation

a) internal documentation

- The comments you put in your source code files should be written to help other

programmers navigate through your code easily in order to find bugs or to determine where to add new features.

Documentation

• There are two types of documentation

b) external documentation

-is made up of the manuals written about the solution

-is written text that accompanies computer software. It either explains how it operates or how to use it, and may mean different things to people in different roles.