Switch-case statements in MATLAB - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple switch-case

What is the output of the following MATLAB code?

MATLAB

x = 3;
switch x
    case 1
        disp('One')
    case 2
        disp('Two')
    case 3
        disp('Three')
    otherwise
        disp('Other')
end

A Three

B Two

C One

D Other

💡 Hint

Check which case matches the value of x.

The variable x is 3, so the switch matches case 3 and displays 'Three'.

❓ Predict Output

intermediate

Switch-case with string input

What will this MATLAB code display?

MATLAB

color = 'red';
switch color
    case 'blue'
        disp('Blue color')
    case 'red'
        disp('Red color')
    case 'green'
        disp('Green color')
    otherwise
        disp('Unknown color')
end

A Blue color

B Red color

C Unknown color

D Green color

💡 Hint

Look at the value of the variable color.

The variable color is 'red', so the switch matches case 'red' and displays 'Red color'.

❓ Predict Output

advanced

Switch-case with multiple values in one case

What does this MATLAB code print?

MATLAB

val = 5;
switch val
    case {1, 3, 5}
        disp('Odd number')
    case {2, 4, 6}
        disp('Even number')
    otherwise
        disp('Other number')
end

A Other number

B Even number

C Odd number

D Error

💡 Hint

Check which group contains the value 5.

The value 5 is in the first case group {1, 3, 5}, so it prints 'Odd number'.

❓ Predict Output

advanced

Switch-case with numeric and string mismatch

What error or output does this MATLAB code produce?

MATLAB

x = 2;
switch x
    case '2'
        disp('String two')
    case 2
        disp('Numeric two')
    otherwise
        disp('No match')
end

A Numeric two

B String two

C No match

D Error

💡 Hint

MATLAB distinguishes between strings and numbers in switch cases.

The variable x is numeric 2, so it matches the numeric case 2, not the string '2'.

❓ Predict Output

expert

Switch-case with cell array and fall-through behavior

What is the output of this MATLAB code?

MATLAB

val = 'b';
switch val
    case {'a', 'b'}
        disp('First group')
    case {'b', 'c'}
        disp('Second group')
    otherwise
        disp('No group')
end

A Second group

B Error

C No group

D First group

💡 Hint

MATLAB switch stops at the first matching case.

The value 'b' matches the first case group {'a', 'b'}, so it prints 'First group' and does not check further cases.

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