ekt150 introduction to computer programmingportal.unimap.edu.my/portal/page/portal30/lecturer...
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EKT150 Introduction to Computer Programming
Wk1-Introduction to Computer and Computer Program
A Brief Look At Computer
Computer
is a device that receives input, stores and processes data, and provides output in a useful format. Computers process data according to sets of instructions called computer programs Example: laptops, PCs, mainframes, even everyday objects such as mobile phones, washing-machines, TV sets, cars contain computers
Hardware Physical components of a computerExample: Keyboard, screen, mouse, disks, memory, CD-ROM, and processing units
Software Programs that run on a computerExample: Operating System such as windows XP -Vista -7, Word processing packages such as MS Word, registration program
Computer Hardware
Exercise :Distinguishing between
input-process-output-storage
The scenario: At the end of each month, a clerk enters the employee name, number of days present and absent, and the number of overtime done in the system. The system then calculates the normal salary, the amount for overtime and the total salary. The clerk then saves the information in the computer hard disk, and takes a backup on a cd. A report is produced for the clerk so that the latter can show to the manager.
Task: Identify the following for that particular system
● Input: the employee name, number of days present and absent, the number of overtime
● Process(es): calculate normal income, calculate amount for overtime, calculate total salary
● Output: Report● Storage: Harddisk, CD-ROM
How Computer Processes Information
Computers are NOT intelligentComputers do what we tell them to do they don’t do anything by themselves.
We must clearly tell a computer what to do in a step by step manner using a programming language.
Computers only understand “electronic”High voltage/low voltage – The machine language
Machine language is binary (two values: high/low) 1’s and 0’s
Why we use computer
Computers produce fast, accurate and reliable results.
While computers do the boring, repetitive, ordinary tasks, we can spend our efforts and time to work on more interesting and creative tasks.
The use of computers in business and manufacturing decreases the cost of goods and services produced.
It is more difficult and needs more time to find or grow up a skill-full labour in IT industry, while buying an additional computer and installing the required software on is easier and cheaper.
Programming / Program / Programmer
Programming in general term is planning or implementation of a task or event command. In the computing field, is instructing a computer to perform specific tasks.
Computer programming can be defined as the process of planning a set of sequence commands to be executed by a computer.
Program be defined as a set of sequence commands that have been determined to be executed by a computer.
Computers are just electronic devices that have the power to perform difficult tasks but they do not ‘KNOW’ what to do therefore - programmers tell the computers what to do by writing programs
Types of Programming languages
Machine language
Strings of numbers giving machine specific instructions Example: +1300042774, +1400593419, +1200274027
Assembly languageEnglish-like abbreviations representing elementary computer operations (translated via assemblers) Example:
LOAD BASEPAYADD OVERPAYSTORE GROSSPAY
High level languageCodes similar to everyday English. Use mathematical notations (translated via compilers) Example Code:
– grossPay = basePay + overTimePay
Example high level languages: C, C++, Cobol, Java, Pascal (Delphi), Basic (Visual Basic) Fortran, SQL, T-SQL, C# …
Programming Problem
Problem that can be solve using programming language.
Suppose you want to add 34 and 56, this is easy. But to add 100 numbers is difficult for us need to use calculator or paper and pencil. Or we can write a program for computer to help us.
Can these problems solve by computer programming?Converting units from kilograms to grams.
Counting the number of cars on a highway.
Finding a life partner
Total rain in a week
How long we live
What we want to eat for dinner
Use of programs to solve problems
Data, Information and Knowledge
Data are the raw facts, gathered from the environment which does not have much meaning. Note: Data is plural, singular form is Datum.
Information is the end product of the processing of data, which has more meaning, and is used in decision making.
Knowledge is the proved and generalized form of information, that is used in strategic planning.
Properties of Well Designed Programs
Well designed programs must be: Correct and accurate
Easy to understand
Easy to maintain and update
Efficient -
Reliable – can be rely on
Flexible – easily adapt in other situation / problem
Correct and
accurate
Easy to understa
nd
Easy to maintain
and update
Efficient Reliable Flexible
Steps involve in programming (Planning)
Requirement Specification: Eliminate ambiguities, Clearly understand the problem
Analyze the problem: Understand the inputs, outputs and processes used for manipulating the data, formulas and constraints
Design: Write the algorithm (flowchart or pseudocode) to represent the solution
Testing and verification: Check the algorithm.
Implement the algorithm: Write a program
Testing and Verification: Check the program
Documentation
Algorithm
An algorithm is the plan for writing a program.
Steps required for solving a problem are listed by using an algorithm tool.
Algorithm tools make program solutions more clear, more understandable, and easier to remember.
Algorithms are written according to rules so that other programmers are also able to read and understand the solution easily.
Tools of Algorithm
There are many Algorithm tools in use, but the most popular ones are Pseudo-Codes and Flowcharts.
In this course for all problems we will use both of these tools but in general you choose only one.
Example flowchart / pseudo-code
Pseudocode
1. Insert key
2. Free the gear
3. Turn on to starting position
4. IF (engine starts in 6 sec)
4.1 YES – go to step 5
4.2 NO – IF (> 5 times)
4.2.1 YES – call workshop go to step 5
4.2.2 NO – go to step 3
5. Release the key 6. End
Structured Programming
All programs can be written using three control structures
RepetitionStatements are executed repeatedly until a condition evaluates to TRUE or FALSE. Example: while, for
SelectionA statement is executed or skipped depending on whether a condition evaluates to TRUE or FALSE. Example: if, switch
SequenceOne statement is executed after another
Flowchart
Flowcharts are graphical tools, containing a set of shapes, each expressing a different action in a sequence of program execution.
There are many different shapes that are used for specific purposes, to avoid complexity, in this course, only a limited subset of these shapes will be shown and used in applications.
Flowchart ShapesTerminal Indicates the starting or ending of the
program
Input Used for data entry from keyboard.
Display Use display on screen
Process Indicates any type of internal operation inside the Processor or Memory (STORE INFORMATION & DO CALCULATIONS -variables)
Decision Used to ask a question that can be answered in a binary format (Yes/No, True/False)
Connector Allows the flowchart to be drawn without intersecting lines or without a reverse flow.
Predefined Process
Used to invoke a subroutine or an interrupt program.
Flowchart: Sequence/Selection/Repetition
Example:Using
Connectors
Pseudo-code
Pseudo-code is structured english that is used as an alternative method to flowcharts for planning structured programs.
There are no general accepted standards for pseudocodes.
We will work with a form that has minimum number of rules and is essentially language-independent.
Pseudo-code instructions are written in English, they can be easily understood and reviewed by users.
The only syntax rules to be concerned with involve the LOOP and SELECTION structures. They must be used as CAPITALISED words.
You can use either one of these assignment statements. We prefer the second one
Pseudo-Code ConstructsAssignment:
– Set num1 to 1
– Num1 =1
Computation
Use all arithmetic operators: addition (+), subtraction (-) . Division (/), multiplication (*), modulus (%) …
Input
Input : to enter from the keyboard
Read : to read from a file
Output
Display : to display on screen
Print : to print on the printer
Selection
IF .. END IF
IF .. ELSE …END IF
IF .. ELSE IF .. ELSE …END IF
SWITCH .. CASE …
Repetition
Repeat …..... Until (condition)
While (condition)
● Begin
:
● End
For (condition)
● Begin
:
● End
Example 1
Write an algorithm that will ask user to input a number then your design will calculate and display the square of input number:
Example 2
Write an algorithm that will ask user to input 10 students' marks and calculate the average students' mark and display all ten marks and the average students' mark:
Exercise
Write an algorithm that will ask user to input height in meters then your design will convert and display the cm value of input numberWrite an algorithm to input a student's mark and determine the student's grade. Use table below to determine the grade
B Grade
>=90 A
80 - 89 B
70 - 79 C
60 - 69 D
< 60 E
References
Yuksel Uckan, Problem Solving Using C,Structured Programming Techniques, McGraw-Hill
Deitel and Deitel, C: How to Program, McGraw-HillCheng, H., “C for Engineers and Scientists”, McGraw Hill, 2010.
Hanly, J.R. and Koffman, E.B., “C Program Design for Engineers”, 2nd Ed., Addison-Wesley, 2001.
ISBN : 0321204174