Multiple outputs in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a function that returns two outputs.

MATLAB

function [a, b] = myFunc(x)
    a = x + 1;
    b = x[1]2;
end

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

A-

B+

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '*' will add 2 instead of doubling.

Using '/' will divide x by 2, which is incorrect here.

The function returns two outputs: 'a' is x plus 1, and 'b' is x multiplied by 2.

2fill in blank

medium

Complete the code to call the function and get both outputs.

MATLAB

[out1, [1]] = myFunc(5);

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

Aout2

Bresult

Coutput

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using only one output variable will ignore the second output.

Using a variable name that does not match the function outputs can cause confusion.

The function returns two outputs, so we capture the second output in 'out2'.

3fill in blank

hard

Fix the error in the function definition to correctly return two outputs.

MATLAB

function [1] = myFunc(x)
    a = x + 1;
    b = x * 2;
end

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

A[a, b]

B<a, b>

C{a, b}

D(a, b)

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses or braces instead of square brackets causes syntax errors.

Omitting brackets leads to only one output being returned.

In MATLAB, multiple outputs are enclosed in square brackets in the function definition.

4fill in blank

hard

Fill both blanks to create a function that returns the sum and product of two inputs.

MATLAB

function [[1], [2]] = sumProd(x, y)
    [1] = x + y;
    [2] = x * y;
end

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

As

Bp

Csum

Dprod

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sum' or 'prod' as variable names can conflict with MATLAB functions.

Mismatching output names in the function signature and body causes errors.

The function returns two outputs named 's' for sum and 'p' for product.

5fill in blank

hard

Fill all three blanks to call the function and display both outputs.

MATLAB

[[1], [2]] = sumProd(3, 4);
disp(['Sum: ', num2str([3])]);

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

AsumVal

BprodVal

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable in disp causes incorrect output display.

Not converting number to string before concatenation causes errors.

We assign outputs to 'sumVal' and 'prodVal', then display the sum using 'sumVal'.

Practice

1. In MATLAB, how do you define a function that returns multiple outputs?

easy

A. Separate output variables with commas without brackets.

B. Use square brackets around output variables in the function definition.

C. Use parentheses around output variables in the function definition.

D. Define each output in a separate function.

Solution

1. Step 1: Understand MATLAB function output syntax

   MATLAB requires multiple outputs to be enclosed in square brackets in the function definition. Only Use square brackets around output variables in the function definition. correctly uses square brackets; others are invalid syntax or incorrect approach.

2. Final Answer:

   Use square brackets around output variables in the function definition. -> Option B

3. Quick Check:

   Multiple outputs = square brackets [OK]

Hint: Remember: multiple outputs always use square brackets [OK]

Common Mistakes:

• Using parentheses instead of square brackets
• Listing outputs without any brackets
• Trying to define outputs in separate functions

2. Which of the following is the correct syntax to call a MATLAB function myFunc that returns two outputs?

easy

A. [a, b] = myFunc(x);

B. a, b = myFunc(x);

C. (a, b) = myFunc(x);

D. a = myFunc(x); b = myFunc(x);

Solution

1. Step 1: Recall MATLAB function call syntax for multiple outputs

   Multiple outputs must be captured using square brackets on the left side of the assignment. [a, b] = myFunc(x); uses correct square brackets; B and C use invalid syntax; A calls function twice, not multiple outputs.

2. Final Answer:

   [a, b] = myFunc(x); -> Option A

3. Quick Check:

   Multiple outputs call = square brackets [OK]

Hint: Use square brackets to capture multiple outputs when calling [OK]

Common Mistakes:

• Using parentheses or commas without brackets
• Calling function multiple times instead of one call
• Missing brackets around output variables

3. What is the output of this MATLAB code?

function [sumVal, diffVal] = calc(a, b)
    sumVal = a + b;
    diffVal = a - b;
end

[x, y] = calc(5, 3);

What are the values of x and y?

medium

A. x = 5, y = 3

B. x = 2, y = 8

C. x = 8, y = 2

D. x = 15, y = 2

Solution

1. Step 1: Trace function execution and match outputs

   The function returns sumVal = a + b = 5 + 3 = 8 and diffVal = a - b = 5 - 3 = 2. x receives sumVal (8), y receives diffVal (2).

2. Final Answer:

   x = 8, y = 2 -> Option C

3. Quick Check:

   sum = 8, diff = 2 [OK]

Hint: First output = sum, second output = difference [OK]

Common Mistakes:

• Swapping order of outputs
• Confusing inputs with outputs
• Adding instead of subtracting for difference

4. Identify the error in this MATLAB function that tries to return two outputs:

function [a, b] = wrongFunc(x)
    a = x * 2;
    b = x + 3
end

medium

A. Square brackets not allowed in output

B. Function must return only one output

C. Function name does not match file name

D. Missing semicolon after assigning b

Solution

1. Step 1: Check syntax line by line

   Line assigning b lacks a semicolon, causing output to print unexpectedly. Multiple outputs with square brackets are allowed; function name matching file is good practice but not error here.

2. Final Answer:

   Missing semicolon after assigning b -> Option D

3. Quick Check:

   Missing semicolon = syntax error [OK]

Hint: Always end statements with semicolon to avoid output [OK]

Common Mistakes:

• Ignoring missing semicolons
• Thinking multiple outputs are not allowed
• Confusing function name and file name mismatch as error

5. You want to write a MATLAB function stats that takes a vector and returns three outputs: the mean, median, and standard deviation. Which function header and call are correct?

hard

A. Function: function [m, med, s] = stats(v)Call: [meanVal, medianVal, stdVal] = stats(data);

B. Function: function (m, med, s) = stats(v)Call: (meanVal, medianVal, stdVal) = stats(data);

C. Function: function m, med, s = stats(v)Call: meanVal, medianVal, stdVal = stats(data);

D. Function: function stats(v) returns m, med, sCall: stats(data)

Solution

1. Step 1: Verify function header and call syntax

   Multiple outputs must use square brackets in the function header: function [m, med, s] = stats(v) and in the call: [meanVal, medianVal, stdVal] = stats(data);. Others use invalid parentheses, commas without brackets, or incorrect formats.

2. Final Answer:

   Function and call with square brackets for multiple outputs -> Option A

3. Quick Check:

   Multiple outputs = square brackets in header and call [OK]

Hint: Use square brackets for multiple outputs in both function and call [OK]

Common Mistakes:

• Using parentheses instead of square brackets
• Not capturing all outputs in call
• Incorrect function header syntax