1. MATLAB – Basic For Loops
Topics Covered:
Loops in MATLAB
- To repeat code
- To access elements of an array
Instructor notes:
This set of slides covers loops, in particular the for-end loop. Also covered is the break command, which allows a program to jump out of a loop prior to reaching the terminal value of the loop counter.
Instructional objectives:
Acquire advanced programming concepts including programming using loops
Use loops (for-end) and break statements in MATLAB for programming
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2. Loops in MatLab What is a Loop ?
A loop allows a group of commands in a program to be repeated.
Each repetition of the loop is called a pass.
Either the number of passes can be fixed.
Or the loop can be terminated after some condition is satisfied.
Instructor notes:
This slide is fairly straightforward. Looping causes a group of commands to be executed repeatedly before moving on to the commands that follow the loop. A loop has a beginning statement, a statement or group of statements that make up its body, and an ending statement.
Each time program execution moves through the loop it is called a pass. The number of passes through a loop can be set to some fixed amount, or the looping can be set to continue until a specified condition is reached. It is very likely, and quite possible, that all of the variables used by a loop will reach new values for each pass.
We’re talking about the first case today (simple use of a fixed number of passes).
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3. Examples of basic for–end Loops
for k = 1:3
disp(k)
end
X=[5, 10, 15, 20];
for i = 1: length(X)
disp(X(i))
end
Output: 1 2 3
Output: 5 10 15 20
Instructor Notes:
These 2 small examples give the essence of the for-end command. The students should type these as programs and then run them to have a feel of how the commands work.
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4. for–end loops with vectors
Create the vector v = [ ]. Calculate and print the square of each element.
Output:
vs = 4
4 16
Program:
v = [ ] ;
for k = 1 : 4
vs(k) = v(k)^2
end
Instructor notes:
This example introduces the student of going through a vector element by element. Very important that the students understand the addressing of vectors using the for-end loop. Note how the output array is being created one element at a time by the computer.
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5. Calculate the factorial of 5
What is a factorial? l
If n=5 and x=1, you continue up to 5
x=x * i
1*1=1
1*2=2
2*3=6
6*4=24
24*5=120
Now, let’s try to have Matlab calculate the factorial of 5..
Presentation Short Title

6. Additional basic for-end loop example
clc
clear
%This script file calculates the factorial of a number
%declare the number you wish to calculate the factorial for
n=5;
%calculate factorial using a for loop
x=1;
for i=1:n
x=x*i;
end
fprintf('The factorial of %i is %i\n',n,x)

7. Matlab Tip of the Day – Dividing your code into Sections
Helps focus on one section of the script file
Reduces overall computation time
Easy to identify errors
Helps create awesome published documents 
Simple to use
All you need is %% (two comment characters or double percent)

8. Using %% - The Steps Start first code section with %%
Write the code for the first section
Use %% again to start the next section and so on
To run only a particular section
Select particular section (by clicking anywhere in the section)
Press Ctrl+Enter
To run overall code or to publish – same as before