1. Announcements
Exercise Sets 2 and 3 Due Thursday

2. MatLab m-file M-file : Used to Store Commands
Script : list of Commands to Run as if Typed
Functions : Code that Call Be Called Later On

3. MatLab Scripts Can Be Called from Command Window Named “scriptName.m”
Called from Command Window by Name (scriptName)
May Use “input” statement to Get User Input
Semi-colon (';') to Suppress Output
MatLab Version of a Program

4. Creating MatLab m-Files
Click on “New” in Upper Left Hand Corner
Opens Editor Window Above Command Window
Type Script (Code) in Editor Window
Save in “.m” File

9. Running MatLab m-Files
Type File Name (without “.m”) in Command Window
Runs All Statements in .m File

12. MatLab Errors Syntax Error : Error in the Script Grammar
Missing parenthesis
Misspelled identifiers
Semantic Error : Error when Running the Script (also called Runtime Error)
Miscalculation
Unexpected Results

16. Selection (if-then-else)
Programming Has 3 Types of Control:
Sequential (normal): Control of Execution Proceeds One after the Other
Selection (if-then-else): Control Proceeds Dependent on Conditions
Iteration (looping): Control Repeated until Condition Met

17. MatLab if Statement Syntax
if condition
statements;
end;
If condition Is True, statements Are Executed
If condition Is False, statements Are Not Executed

18. Conditional Operators
Relational Operators: < , > , >= , <=
Equality Operators: == , ~=
Comparing Strings :
strcmp(str1, str2)
Returns true or false

19. Selection Examples if age < 30 disp('You are very very Young'); end
if strcmp(grade , 'A')
disp('Congratulations!');
if ~strcmp(grade,'F')
disp('You passed!');

20. else Statement Syntax: if (condition) else end
statement(s); //condition true
else
statement(s); //condition false
end

21. if-else Example if myGrade >= 60 disp('You passed!'); else
disp('How about them Cubs?');
end

22. Nested if Statements if myGrade >= 80 if myGrade >= 90
disp('You have an A!');
else
disp('You have a B!');
end
disp('We''ll give you a C.');

23. if/else (Cascaded) if myGrade > 90 disp('A!');
else if myGrade > 80
disp('B!');
else if myGrade > 70
disp('C!');
else
disp('Oh-oh!');
end

24. Logical Operators
A Boolean Expression Is an Expression with a Value of Either True or False
A Logical Operator Is One Used to Further Specify True or False in an Expression
Connects Two or More Expressions Together
&& Is Logical “AND”
|| Is Logical ‘OR”
&&: Both Operands Must Be True for Entire Expression to Be True
||: Only One (or Both) of the Operands Must Be True for Entire Expression to Be True
~ is Logical “Not” (Take Opposite of Boolean Expression)

25. Logical Operators if numStudents > MIN && numStudents < MAX
classRun = 1;
else
classRun = 0;
end
if numStudents > MAX || numInstructors == 0
if classRun
disp('Class will Run!');

26. Operator Precedence () ~ (not) *, /, % +, -
<, <=, >, >= (Relational Operators)
==, ~= (Equality Operators)
&& (Logical AND)
|| (Logical OR)
= (ASSIGNMENT)

27. Multiple Logical Operators
if num1 > MAX || num2 == 0 && num3 == 0
disp('num1 is MAX or something is 0');
end
disp('I think…..');

28. Switch Statements Also Called Switch/Case Statement
Just Case in Other Languages
Selects Among Several Different Actions
If Value Is Matched, Statements under Control of that Case Block Are Executed

29. Switch Case Example 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

30. Switch Case Example BASERATE = 200; n = input('Enter Passengers: ');
switch n
case 2
rate = BASERATE * 0.80;
case 4
rate = BASERATE * 0.75;
case 5
rate = BASERATE * 0.55;
otherwise
rate = BASERATE;
end
out1 = sprintf('Your rate is %.2f',rate);
disp(out1);

31. Switch Case Example BASERATE = 200; n = input('Enter Passengers: ');
switch n
case {2,3}
rate = BASERATE * 0.80;
case 4
rate = BASERATE * 0.75;
case 5
rate = BASERATE * 0.55;
otherwise
rate = BASERATE;
end
out1 = sprintf('Your rate is %.2f',rate);
disp(out1);

32. Switch Case Example cmd = input('Enter a command: ','s'); switch cmd
case 'left'
disp('going left')
case 'right'
disp('going right')
case 'up'
disp('going up')
otherwise
disp('unknown command')
end