Chapter 1 _ 2_IntroToProgramming.pptx

BCI1103 Computer Programming (SFK)

 To know basic information about computer programming
 To get familiar with algorithm, pseudo-code and flowchart
 To know computer programming language

 Computer programs, known as software, are instructions to the computer.
 Programming began in the 1940s, using memory addresses and machine code
directly.
 Older programs were “monolithic,” and ran from beginning to end.
 Programs are written using programming languages.
 Newer programs contain modules that can be combined to form programs.

1101101010011010
COBOL (COmmon Business Oriented Language)
FORTRAN (FORmula TRANslation)
BASIC (Beginner All-purpose Symbolic Instructional
Code)
Pascal (named for Blaise Pascal)
Ada (named for Ada Lovelace)
C (whose developer designed B first)
Visual Basic (Basic-like visual language developed by
Microsoft)
Delphi (Pascal-like visual language developed by
Borland)
C++ (an object-oriented language, based on C)
Java (an object-oriented language)
Python

 Algorithm, pseudo-code, flowchart
 Algorithm?  the list of instructions and rules that a computer needs to do to
complete a task
 Algorithm  pseudo-code or flowchart or both
 Pseudo-code?  a plain language description of the steps in an algorithm
 Flowchart?  a diagram that depicts a process, system or computer algorithm

 Task:
Write an algorithm to calculate an area based on a given width and length. The
area is width multiply length.
Pseudo-code:
Input: a width and a length
1. Calculate the area by multiplying the width and
length
2. Print out the area
Output: area
Input
Process
Output

 Task:
Write an algorithm to determine a student’s final grade and indicate whether it is
passing or failing. The final grade is calculated based on the average of four marks.
If the average mark is below than 50, the grade is FAIL and vice versa.
Pseudo-code:
Input: User enter Final Grade of students
1. Calculate Average
2. Check student mark if lower or higher than 50
Output: output fail or pass

 Task:
Write an algorithm to
calculate an area based on
a given width and length.
The area is width
multiply length.
Flowchart
Start
Enter width,
length
Area = width x
length
Print area
End

 Flowchart  symbols that
represent certain meaning

 Python  Thonny (IDE)
 Script  to write your code
 Shell  to execute the written code
 Variable  to view your variables name and value

Python Script
Write code in here
Shell
Input / Output
displayed here
Variables (name,
value)/ Help/ Notes

 Step 1: Create new file: click File  New  name your file
 Step 2: Write code in the script
 Step 3: Click File  Save or “ctrl+s”
 Step 4: Click Run to execute the code

 The output will be displayed in the Shell

Pseudo-code:
Input: width, length
1. area = width * length
2. print area
Output: area

 We cannot see the process on computer screen because the processes occur in
computer memory and CPU (the brain of computer).
 We can see the variables name and the values that have been executed.
 Program execution is ended when there is no more code after the last line.

 Computer program contain codes of instructions, telling computer what to do.
 The instructions are written by you as the programmer (a person writing
computer codes).
 The written instructions (codes) are stored in files (computer system).
 It is executed (start doing all the actions), when you open or execute the
program in computer system.

 How to write scripts to solve a problem?  do the step by step in flowchart and
pseudo-code
 The steps must be based on the logic to solve the problem.
 Logic Syntax and Semantic logic
 Syntax  formal rules - how valid instructions are written in a programming
language  the code must be written based on valid rules in the python (eg.:
print (“ “))
 Semantic  set of rules that determines the instruction’s meaning in a
programming languages  eg.: to calculate area, you need to have the width
and length value, you cannot write the area calculation before having the
values.

 Identifiers: to name variables
 Formed by combining letters, digits and underscore
 Case sensitive.
 2 categories:-
 Standard
 User-defined

 Case sensitive.
 2 categories:-
 Standard
 User-defined
• print
• if
• else
• continue
• True
• False
• while
• break
………….. Python keywords  already have in python that
have specific function/instruction

 Case sensitive.
 2 categories:-
 Standard
 User-defined
Programmer (you) can define it.
• width
• length
• area
• firstName
• lastName
The rules:
1. Variables can be a combination of letters in lowercase (a to z) or
uppercase (A to Z) or digits (0 to 9) or an underscore _. Names like
myClass, var_1 and print_this_to_screen, all are valid example.
2. Cannot start with digit: 1var
3. Cannot use the python keywords.
4. Cannot use special symbols: ! @ # $ % ^ & * ( ).
5. Must be meaningful: first_Name, not nm;

 Case sensitive.
 2 categories:-
 Standard
 User-defined
 Let’s analyze the program

What if?:

force = mass x gravity

volume = pi x height x radius2
What if?:

 https://www.programiz.com/python-programming
 https://www.tutorialspoint.com/python/index.htm
 https://www.w3schools.com/python/

Chapter 1 _ 2_IntroToProgramming.pptx

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