Computer Programming
Course code : EEN 170
Comm. Hours: 2hr theory & 2hr practical
Goals of This Chapter
1. Familiarizing ourselves with the Matlab Environment
2. Learning basic operations
3. Learning to use Matlab as a simple calculator
4. Writing our first script
5. Learning to use the Help!!!
Computer Structure - Hardware
CPU
Input devices
Memory
Storage devices
Output devices
Computer Structure - Software
Software
Operating system
Gives services to
software:
Hardware
 Access input/output
devices
 Memory allocations
 And much more…
5
From Thoughts to Program
I want to add
one and one
Human
language
1+1
mambo-jumbo
010011010011
compiler
Matlab
language
Intermediate
language
Computer
language
Operating
System
6
WHAT IS MATLAB?
Matlab is a powerful computing system for handling
the calculations involved in scientific and engineering
problems.
An interactive program that is suitable for running
computations, drawing graphs and much more (graphical
interface).
A programming language for technical computing (scripts).
The name MATLAB stands for MATrix LABoratory.
THE MATLAB DESKTOP
Command Window
To execute commands in the MATLAB environment
Command line
Matlab as a calculator:
Lets run our first command:
1+1
9
Command Window
Previous Command line
Output (answer)
Current Command line
 The output is displayed
 Get the previous command by pressing up
arrow keyboard
 Can clear window using the command clc
10
Workspace Window
Displays all the defined variables
Workspace Window
All workspace variables
Variable value
11
Command History Window
Displays record of the commands used
Command History Window
History
Try drag the command to
the command window
12
The semicolon ( ; ):
If a semicolon (;) is typed at the end of a command the output of the command is
not displayed.
Typing %:
When the symbol % (percent) is typed at the beginning of a line, the line is
designated as a comment. This means that when the Enter key is pressed the line is
not executed.
The clc command:
The clc command (type clc and press Enter) clears the Command Window.
Clear
Removes all variables from the memory.
clear x y z
Removes only variables x, y, and z from the memory.
who
Displays a list of the variables currently in the memory.
Whos
Displays a list of the variables currently in the memory and their sizes
together with information about their bytes and class
ARITHMETIC OPERATIONS WITH SCALARS
The symbols of arithmetic operations are:
Operation
Addition
Symbol
+
Example
5+3
Subtraction
–
5–3
Multiplication
*
5 *3
Right division
/
5/3
Left division
\
5\3 =3/5
Exponentiation
^
5 ^ 3 ( means 53 = 125)
Order of Precedence
MATLAB executes the calculations according to the order of
precedence displayed below.
Precedence Mathematical Operation
First
Parentheses. For nested parentheses, the innermost
are executed first.
Second
Exponentiation.
Third
Multiplication, division (equal precedence).
Fourth
Addition and subtraction.
If two or more operations have the same precedence, the expression is executed
from left to right.
Lets Try Matlab as a Calculator

I want to make a fruit salad for
10 people.
Ingredients for 5 people:
6
oranges
5
bananas
3
apples
1
melon



What is the total num of fruits
needed?
How much will it cost to make
the salad?
Answer:
Price list:
orange
1.5
banana
1.2
apple
1
melon
5
17
DISPLAY FORMATS
The user can control the format in which MATLAB displays output
on the screen
ELEMENTARY MATH BUILT-IN FUNCTIONS
MATLAB has a very large library of built-in functions. A function has a
name and an argument in parentheses
Some commonly used elementary MATLAB mathematical built-in functions
Trigonometric math functions
Rounding functions
The Assignment Operator
In MATLAB the = sign is called the assignment operator.
The assignment operator assigns a value to a variable.
Variable_name = A numerical value, or a computable expression
Rules About Variable Names
A variable can be named according to the following rules:
• Must begin with a letter.
• Can be up to 63 characters long.
• Can contain letters, digits, and the underscore character.
• Cannot contain punctuation characters (e.g., period, comma, semicolon).
• MATLAB is case sensitive: it distinguishes between uppercase and lowercase letters.
For example, AA, Aa, aA, and aa are the names of four different variables.
• No spaces are allowed between characters (use the underscore where a space is
desired).
• Avoid using the name of a built-in function for a variable (i.e., avoid using cos,
sin, exp, sqrt, etc.). Once a function name is used to define a variable, the
function cannot be used.
Variable Assignment
max_grade = 100;
Variable identifier (name):
•
Letters
•
Digits
•
Underscore
1. Can’t start with a number
2. Case sensitive!!!
3. Can’t be a keyword
Value
Assignment
operator
Keywords and Predefined Variables
There are 20 words, called keywords, that are reserved by MATLAB for
various purposes and cannot be used as variable names. These words
are:
break
Elseif
otherwise
try
Keywords
pi
Eps
Inf
i ,j
NaN
case
end
parfor
while
catch
classdef
for
function
persistent return
continue
global
spmd
else
if
switch
The number π.
The smallest difference between two numbers. Equal to 2^(–52),
Used for infinity.
Defined as , which is: 0 + 1.0000i.
Stands for Not-a-Number. Used when MATLAB cannot determine a
numeric value. Example: 0/0.
valid