Input and output arguments in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a function that takes one input argument.

MATLAB

function result = square[1]
    result = x^2;
end

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

A{x}

B[x]

C(x)

D<x>

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets [] instead of parentheses for inputs.

Using curly braces {} which are for cell arrays, not inputs.

In MATLAB, input arguments are enclosed in parentheses ().

2fill in blank

medium

Complete the code to define a function that returns two output arguments.

MATLAB

function [sum, diff] = addAndSubtract[1]
    sum = a + b;
    diff = a - b;
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 square brackets for input arguments.

Using curly braces or angle brackets which are invalid.

Input arguments are always enclosed in parentheses (). Output arguments are enclosed in square brackets [].

3fill in blank

hard

Fix the error in the function definition to correctly specify output arguments.

MATLAB

function [1] = addAndSubtract(a, b)
    sum = a + b;
    diff = a - b;
end

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

A[a, b]

B[sum, diff]

C(a, b)

D(sum, diff)

Attempts:

3 left

💡 Hint

Common Mistakes

Not using square brackets for multiple outputs.

Placing output variables outside brackets or parentheses.

Output arguments must be enclosed in square brackets before the equals sign.

4fill in blank

hard

Fill both blanks to create a function that returns the square and cube of input x.

MATLAB

function [[1], [2]] = powers(x)
    [1] = x^2;
    [2] = x^3;
end

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

Asquare

Bcube

Cpow2

Dpow3

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names that don't match the assignments inside the function.

Mixing up the order of outputs.

The output variables should be named square and cube to match the assignments inside the function.

5fill in blank

hard

Fill all three blanks to define a function that returns the sum, product, and difference of two inputs.

MATLAB

function [[1], [2], [3]] = calc(a, b)
    [1] = a + b;
    [2] = a * b;
    [3] = a - b;
end

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

Asum

Bprod

Cdiff

Dresult

Attempts:

3 left

💡 Hint

Common Mistakes

Using generic names like result instead of descriptive output names.

Mixing up the order of output variables.

Output variables must be sum, prod, and diff to match the calculations inside the function.

Practice

1. What is the main purpose of input arguments in a MATLAB function?

easy

A. To send data into the function for processing

B. To display results on the screen

C. To store variables permanently

D. To create new functions inside the main function

Solution

1. Step 1: Understand input arguments

   Input arguments are values or data you give to a function so it can use them inside.

2. Step 2: Identify the purpose

   The main purpose is to send data into the function for it to work on.

3. Final Answer:

   To send data into the function for processing -> Option A

4. Quick Check:

   Input arguments = send data in [OK]

Hint: Input arguments bring data into functions [OK]

Common Mistakes:

• Confusing input arguments with output arguments
• Thinking input arguments display results
• Assuming input arguments create new functions

2. Which of the following is the correct syntax to define a MATLAB function with one input and one output argument?

easy

A. function output = myFunc(input)

B. function myFunc(input) = output

C. function (output) = myFunc input

D. function myFunc output(input)

Solution

1. Step 1: Recall MATLAB function syntax

   The correct syntax starts with 'function', then output, '=', function name, and input in parentheses.

2. Step 2: Match the syntax

   function output = myFunc(input) matches this pattern exactly: function output = myFunc(input)

3. Final Answer:

   function output = myFunc(input) -> Option A

4. Quick Check:

   Syntax = function output = name(input) [OK]

Hint: Output = functionName(input) is the right order [OK]

Common Mistakes:

• Placing output after function name without '='
• Missing parentheses around input
• Using '=' incorrectly in function header

3. What will be the output of the following MATLAB function call?

function y = squarePlusOne(x)
    y = x^2 + 1;
end

result = squarePlusOne(3);

medium

A. 9

B. 10

C. 7

D. 16

Solution

1. Step 1: Calculate the square of input

   Input x is 3, so x^2 = 3^2 = 9.

2. Step 2: Add 1 to the squared value

   9 + 1 = 10.

3. Final Answer:

   10 -> Option B

4. Quick Check:

   3 squared plus 1 = 10 [OK]

Hint: Square input, then add one [OK]

Common Mistakes:

• Forgetting to add 1 after squaring
• Using multiplication instead of power
• Confusing output with input

4. Identify the error in this MATLAB function definition:

function output = addNumbers(a, b)
    output = a + b
end

medium

A. Input arguments must be in square brackets

B. Function name should be capitalized

C. Output variable cannot be named 'output'

D. Missing semicolon after output assignment

Solution

1. Step 1: Check MATLAB syntax rules

   Each statement should end with a semicolon to suppress output in functions.

2. Step 2: Identify missing semicolon

   The line 'output = a + b' lacks a semicolon at the end.

3. Final Answer:

   Missing semicolon after output assignment -> Option D

4. Quick Check:

   Statements need semicolons [OK]

Hint: End statements with semicolon inside functions [OK]

Common Mistakes:

• Ignoring semicolon causes unwanted output
• Thinking function names must be capitalized
• Using wrong brackets for inputs

5. You want to write a MATLAB function that takes two numbers as input and returns both their sum and product as outputs. Which function header is correct?

hard

A. function sum, product = calculate(a, b)

B. function calculate(a, b) = [sum, product]

C. function [sum, product] = calculate(a, b)

D. function calculate = [sum, product](a, b)

Solution

1. Step 1: Recall syntax for multiple outputs

   Multiple outputs are enclosed in square brackets before the '=' sign.

2. Step 2: Match correct syntax

   function [sum, product] = calculate(a, b) uses square brackets for outputs and correct order: function [sum, product] = calculate(a, b)

3. Final Answer:

   function [sum, product] = calculate(a, b) -> Option C

4. Quick Check:

   Multiple outputs use square brackets [OK]

Hint: Use square brackets for multiple outputs [OK]

Common Mistakes:

• Omitting square brackets for multiple outputs
• Placing outputs after function name without brackets
• Using '=' incorrectly in function header