Switch-case statements in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a switch-case statement for variable color.

MATLAB

switch [1]
    case 'red'
        disp('Stop');
    otherwise
        disp('Go');
end

Drag options to blanks, or click blank then click option'

Avalue

Bcase

Cif

Dcolor

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'case' instead of the variable name after switch.

Using 'if' which is a different control structure.

The switch statement must be followed by the variable you want to check, here color.

2fill in blank

medium

Complete the code to display 'Go' when the color is not 'red'.

MATLAB

switch color
    case 'red'
        disp('Stop');
    [1]
        disp('Go');
end

Drag options to blanks, or click blank then click option'

Aelse

Bcase 'green'

Cotherwise

Ddefault

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'else' which is not valid in MATLAB switch-case.

Using 'default' which is not a MATLAB keyword.

The otherwise keyword handles all cases not matched by previous case labels.

3fill in blank

hard

Fix the error in the switch-case syntax by completing the missing keyword.

MATLAB

switch day
    [1] 'Monday'
        disp('Start of week');
    case 'Friday'
        disp('End of week');
end

Drag options to blanks, or click blank then click option'

Acase

Bif

Cswitch

Dotherwise

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the 'case' keyword before the condition.

Using 'if' inside switch-case which is incorrect.

Each condition in a switch-case must start with the case keyword.

4fill in blank

hard

Fill both blanks to create a switch-case that displays 'Weekend' for Saturday and Sunday.

MATLAB

switch day
    [1] 'Saturday'
        disp('Weekend');
    [2] 'Sunday'
        disp('Weekend');
    otherwise
        disp('Weekday');
end

Drag options to blanks, or click blank then click option'

Acase

Botherwise

Dswitch

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'otherwise' or 'switch' instead of 'case' for conditions.

Each condition in a switch-case must start with the case keyword.

5fill in blank

hard

Fill all three blanks to create a switch-case that prints the day type based on the variable day.

MATLAB

switch [1]
    case 'Saturday'
        disp([2]);
    case 'Monday'
        disp([3]);
    otherwise
        disp('Midweek');
end

Drag options to blanks, or click blank then click option'

Aday

B'Weekend'

C'Start of week'

Dcolor

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong variable name in the switch statement.

Not using quotes around the strings to display.

The switch statement checks the variable day. For 'Saturday' it displays 'Weekend', and for 'Monday' it displays 'Start of week'.

Practice

1. What is the main purpose of a switch-case statement in MATLAB?

easy

A. To repeat a block of code multiple times

B. To create a new variable

C. To define a function

D. To execute different blocks of code based on the value of a variable

Solution

1. Step 1: Understand the role of switch-case

   A switch-case statement chooses which code to run depending on a variable's value.

2. Step 2: Compare with other options

   Repeating code is done by loops, defining functions is different, and creating variables is unrelated.

3. Final Answer:

   To execute different blocks of code based on the value of a variable -> Option D

4. Quick Check:

   Switch-case selects code by value [OK]

Hint: Switch-case runs code based on one variable's value [OK]

Common Mistakes:

• Confusing switch-case with loops
• Thinking switch-case defines functions
• Assuming switch-case creates variables

2. Which of the following is the correct syntax to start a switch-case block in MATLAB?

easy

A. switch variable

B. case variable

C. switch-case(variable)

D. switch = variable

Solution

1. Step 1: Recall switch-case syntax

   The switch statement starts with the keyword switch followed by the variable name.

2. Step 2: Check each option

   switch variable matches correct syntax. Options A, B, and C are invalid MATLAB syntax for switch.

3. Final Answer:

   switch variable -> Option A

4. Quick Check:

   Start switch with 'switch variable' [OK]

Hint: Start switch with 'switch' plus variable name [OK]

Common Mistakes:

• Using parentheses after switch
• Writing 'case' instead of 'switch' to start
• Assigning variable with '=' in switch

3. What will be the output of this MATLAB code?

color = 'green';
switch color
    case 'red'
        disp('Stop')
    case 'green'
        disp('Go')
    otherwise
        disp('Wait')
end

medium

A. Go

B. Wait

C. Stop

D. Error

Solution

1. Step 1: Check the value of variable 'color'

   The variable color is set to 'green'.

2. Step 2: Match the case in switch

   The switch checks cases: 'red' (no), 'green' (yes), so it runs disp('Go').

3. Final Answer:

   Go -> Option A

4. Quick Check:

   color='green' triggers 'Go' [OK]

Hint: Match variable value to case labels to find output [OK]

Common Mistakes:

• Choosing output from wrong case
• Ignoring the otherwise block
• Assuming syntax error

4. Identify the error in this MATLAB switch-case code:

value = 10;
switch value
case 5
    disp('Five')
case 10
    disp('Ten')
case
    disp('Other')
end

medium

A. Incorrect variable name in switch

B. Missing 'otherwise' keyword for default case

C. Missing 'end' statement

D. Case values must be strings

Solution

1. Step 1: Review the case statements

   The last case has no value and no keyword 'otherwise'. MATLAB requires 'otherwise' for default.

2. Step 2: Check syntax rules

   Case values can be numbers, 'end' is present, variable name is correct.

3. Final Answer:

   Missing 'otherwise' keyword for default case -> Option B

4. Quick Check:

   Default case needs 'otherwise' keyword [OK]

Hint: Use 'otherwise' for default case, not empty case [OK]

Common Mistakes:

• Leaving case without value or otherwise
• Thinking 'end' is missing
• Believing case values must be strings

5. You want to write a MATLAB switch-case that prints 'Weekend' for days 'Saturday' and 'Sunday', 'Weekday' for Monday to Friday, and 'Invalid' otherwise. Which code correctly implements this?

hard

A. switch day
case ['Saturday', 'Sunday']
disp('Weekend')
case ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday']
disp('Weekday')
otherwise
disp('Invalid')
end

B. switch day
case 'Saturday' || 'Sunday'
disp('Weekend')
case 'Monday' || 'Tuesday' || 'Wednesday' || 'Thursday' || 'Friday'
disp('Weekday')
otherwise
disp('Invalid')
end

C. switch day
case {'Saturday', 'Sunday'}
disp('Weekend')
case {'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'}
disp('Weekday')
otherwise
disp('Invalid')
end

D. switch day
case 'Saturday', 'Sunday'
disp('Weekend')
case 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'
disp('Weekday')
otherwise
disp('Invalid')
end

Solution

1. Step 1: Understand how to group cases in MATLAB

   MATLAB allows grouping multiple values in a cell array inside case, like {'Saturday', 'Sunday'}.

2. Step 2: Check each option's syntax

   switch day case {'Saturday', 'Sunday'} disp('Weekend') case {'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'} disp('Weekday') otherwise disp('Invalid') end uses correct cell arrays for grouping. switch day case 'Saturday' || 'Sunday' disp('Weekend') case 'Monday' || 'Tuesday' || 'Wednesday' || 'Thursday' || 'Friday' disp('Weekday') otherwise disp('Invalid') end uses invalid '||' inside case. switch day case ['Saturday', 'Sunday'] disp('Weekend') case ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'] disp('Weekday') otherwise disp('Invalid') end uses square brackets which is wrong for strings. switch day case 'Saturday', 'Sunday' disp('Weekend') case 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday' disp('Weekday') otherwise disp('Invalid') end uses commas incorrectly.

3. Final Answer:

   Code with cell arrays for grouped cases -> Option C

4. Quick Check:

   Group cases with cell arrays {} in switch-case [OK]

Hint: Group multiple cases using curly braces {} [OK]

Common Mistakes:

• Using || inside case labels
• Using square brackets for string groups
• Separating cases with commas instead of cell arrays