During this session, we introduce some of the most basic and important data classes of MATLAB: the numeric array and the cell array. We will handle the change of a string into a number, in relation to user input. We will do a small introduction to the assert() function, which we can use to check if a program is working as intended. Further, we will have a quick look at basic control flow - for-loop.

1. PROGRAMMING SESSIONS
02
User input / Fundamental MATLAB classes
’assert’ / ’for’ statement
Rafael Camacho

2. PROGRAM
Some basic concepts
• Input – prompt
• Object,Type andVariables –
Variable definition
• Operations and operators
MATLAB programming
• Fundamental MATLAB classes
• How to prompt the user for
input
• Assertion, why is it useful?
• Flow control, for statement
• Now that we can do I/O we
can write our first useful
program
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3. BASIC CONCEPTS
INPUT - PROMPT
• In session-01 we created a basic
program that wrote to the screen or
text file. It does output. However,
useful programs generally produce
results based on some input given to
them.Together output and input are
known as I/O.
• When we encourage the user to
enter an input (take an action) we call
it a prompt.
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4. BASIC CONCEPTS
OBJECTS, TYPE & VARIABLES
• To store input we need a place in the computer’s memory
to place it:
” An object is a region of memory with a type that specifies what
kind of information can be placed in it. A named object is called a
variable.” Stroustrup – Programming… (2nd edition)
• A statement that introduces a new variable is called a
definition
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1988
Type: int - integer
Name: year
Variable
Value

5. BASIC CONCEPTS
OPERATIONS AND OPERATORS
• The type of a variable defines what kind of information can
be placed into the object. Moreover, it also defines which
operations can be applied to the variable and they mean.
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Fly!
?!
Operation double char string
assignment = = =
addition + +*
Cast to double
+*
Cast to
double
concatenation cat; [] cat; [] cat; []
greater than > > >*
Dimensions
must agree
Examples from MATLAB

6. FUNDAMENTAL MATLAB CLASSES
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Image from Mathworks

7. MATLAB
HOW TO PROMPT THE USER
We will first concentrate in
receiving data (input) from
the user via the keyboard.
Later on we will explore
other ways a program can
receive input.
The functions we will
explore today are:
• input
• inputdlg
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8. ASSERTION
• Why is assertion important:
Extract from wikipedia:
“Programmers can use assertions to help
specify programs and to reason about
program correctness. For example,
a precondition—an assertion placed at the
beginning of a section of code—
determines the set of states under which
the programmer expects the code to
execute.A postcondition—placed at the
end—describes the expected state at the
end of execution.”
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9. FLOW CONTROL
• For loops are used for iteration:
repeating a part of code several times.
In MATLAB a basic for loop looks like:
• for i=1:10
• disp(num2str(i))
• end
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10. NOW LETS CODE
Let there be code!
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