1. ECE 1304 Introduction to Electrical and Computer Engineering
Section 1.10
Program Structures in MATLAB

2. What is a Computer Program?
A series of commands that instruct the computer to take information and do something useful with it.

3. Simple Procedural Program
Start
Input Data
Perform Calculations
Output Data
End

4. Program with a Branching Structure
Start
Input Data 1
Option 1 Calculations ?
Option 0 Calculations
Output Data
End

5. Program with a Branching Structure1 ? 1 ? ? 1

6. Program with a Branching Structure1 ? 1 1 ? ?

7. Program with a Looping Structure
Start
Input Data
Loop
Calculations 1 ?
Output Data
End

8. A Menu Driven Structure Method
Main Menu
1. Option 1
2. Option 2
End
Input Choice?
Start 1
1 ?
Option 1 1
2 ?
Option 2 1
End ?
End

9. Programming Structures in MATLAB
MATLAB provides for programming structures using
Conditional Statements
Loops

10. Conditional Statements
The general form for conditional statements is
if (conditional_expression)
statements
end
The conditional expressions use one of the relational operators, ==, >, >=, etc.

11. Conditional Statements
The general form for conditional statements is
if (conditional_expression_1)
statements_1
elseif (conditional_expression_2)
statements_2
else
statements_3
end
The conditional expressions use one of the relational operators, ==, >, >=, etc.

12. Example Conditional Statements
Assuming x has a scalar value
if (x >= 0)
y = sqrt(x)
end
else
y = -sqrt(-x)

13. Example Conditional Statements
Assuming x has a scalar value
if (x >= 25)
y = 50*sqrt(x)
elseif (x >= 0)
y = 10*x
else
y = 0
end

14. Loops MATLAB has two structures for loops:
for (counter = start:increment:end)
statements
end
while (conditional_expression)

15. Example Loops m = 0; x(1) = 10; for k = 2:3:11; m = m + 1;
x(m+1) = x(m) + k^2;
end

16. Example Loops x = 5; k = 0; while (x < 25); k = k + 1; y(k) = 3*x;
x = 2*x-1;
end

17. Switch – Case Structure
switch switch_expression
case case_expression
statements
...
otherwise
end

18. Switch – Case Structure
n = input('Enter a number: '); switch n
case -1
disp('negative one')
case 0
disp('zero')
case 1
disp('positive one')
otherwise
disp('other value')
end