First MATLAB program - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the command to display text in MATLAB?

The command disp() is used to display text or variables in MATLAB.

beginner

How do you write a comment in MATLAB?

Use the percent sign % at the start of a line or after code to add a comment.

beginner

What does the following MATLAB code do?

disp('Hello, world!')

It prints the text Hello, world! to the command window.

beginner

How do you run a MATLAB script named hello.m?

Type the script name hello (without .m) in the command window and press Enter.

beginner

What is the file extension for MATLAB scripts?

MATLAB scripts are saved with the .m file extension.

Which command shows text output in MATLAB?

A show()

B print()

C echo()

D disp()

The disp() command is used to display text or variables in MATLAB.

How do you start a comment in MATLAB?

A %

B #

C //

D /*

Comments in MATLAB start with the percent sign %.

What will this code print?

disp('Hi!')

A Hi!

B disp('Hi!')

C Error

D Nothing

The disp() function prints the text inside the quotes.

What is the correct way to run a script named test.m?

A execute test.m

B run test.m

C test

D start test

In MATLAB, you run a script by typing its name without the .m extension.

What file extension do MATLAB scripts use?

A .mat

B .m

C .mlx

D .txt

MATLAB scripts are saved with the .m extension.

Explain how to write and run your first MATLAB program that prints 'Hello, world!'

Think about how you show messages and how you run scripts in MATLAB.

Describe how to add comments in MATLAB and why they are useful.

Comments help others and yourself understand your code.

Practice

1. What does the MATLAB command disp('Hello, world!') do?

easy

A. It saves the text Hello, world! to a file.

B. It displays the text Hello, world! on the screen.

C. It creates a variable named Hello, world!.

D. It runs a loop that prints Hello, world! multiple times.

Solution

1. Step 1: Understand the disp function

   The disp function in MATLAB shows text or values on the screen.

2. Step 2: Analyze the input to disp

   The input is a string 'Hello, world!' which means it will print this exact text.

3. Final Answer:

   It displays the text Hello, world! on the screen. -> Option B

4. Quick Check:

   disp('text') shows text [OK]

Hint: disp shows text inside single quotes [OK]

Common Mistakes:

• Thinking disp saves text to a file
• Using double quotes instead of single quotes
• Confusing disp with variable creation

2. Which of the following is the correct syntax to display the message Hello in MATLAB?

easy

A. disp('Hello')

B. display(Hello)

C. disp(Hello)

D. print('Hello')

Solution

1. Step 1: Check the correct function name

   MATLAB uses disp to display messages, not display or print.

2. Step 2: Check the string syntax

   Strings must be inside single quotes in MATLAB, so disp('Hello') is correct.

3. Final Answer:

   disp('Hello') -> Option A

4. Quick Check:

   disp with single quotes is correct [OK]

Hint: Use disp with single quotes for text [OK]

Common Mistakes:

• Using double quotes instead of single quotes
• Using wrong function names like print or display
• Missing quotes around text

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

disp('Welcome to MATLAB!')

medium

A. Welcome to MATLAB!

B. disp('Welcome to MATLAB!')

C. SyntaxError

D. No output

Solution

1. Step 1: Understand disp function behavior

   The disp function prints the string inside the parentheses to the screen.

2. Step 2: Check the string format

   The string is correctly enclosed in single quotes, so it will print exactly as given.

3. Final Answer:

   Welcome to MATLAB! -> Option A

4. Quick Check:

   disp prints string text [OK]

Hint: disp prints text inside single quotes exactly [OK]

Common Mistakes:

• Expecting disp to print the command itself
• Using double quotes causing errors
• Forgetting to use disp function

4. Identify the error in this MATLAB code:

disp(Welcome to MATLAB!)

medium

A. Parentheses are not allowed with disp

B. Missing semicolon at the end

C. disp function does not exist

D. Text is not inside single quotes

Solution

1. Step 1: Check the input to disp

   The text Welcome to MATLAB! is not inside single quotes, so MATLAB treats it as variables or commands.

2. Step 2: Understand string syntax in MATLAB

   Strings must be enclosed in single quotes to be recognized as text.

3. Final Answer:

   Text is not inside single quotes -> Option D

4. Quick Check:

   Strings need single quotes [OK]

Hint: Always put text inside single quotes in disp [OK]

Common Mistakes:

• Omitting quotes around text
• Thinking semicolon is required for disp
• Believing disp is not a function

5. You want to write a MATLAB program that displays two lines:
Hello
and
Welcome to MATLAB
Which code will do this correctly?

hard

A. disp('Hello\nWelcome to MATLAB')

B. disp('Hello')
disp(Welcome to MATLAB)

C. disp('Hello')
disp('Welcome to MATLAB')

D. disp('Hello' + 'Welcome to MATLAB')

Solution

1. Step 1: Check how to display multiple lines

   Using two separate disp calls prints each line separately.

2. Step 2: Analyze each option

   disp('Hello') disp('Welcome to MATLAB') uses two disp calls with correct strings. disp('Hello\nWelcome to MATLAB') tries to use \n inside single quotes which MATLAB does not interpret as newline. disp('Hello') disp(Welcome to MATLAB) misses quotes in second disp. disp('Hello' + 'Welcome to MATLAB') tries to add strings which is invalid in MATLAB.

3. Final Answer:

   disp('Hello') disp('Welcome to MATLAB') -> Option C

4. Quick Check:

   Use separate disp calls for multiple lines [OK]

Hint: Use separate disp lines for multiple messages [OK]

Common Mistakes:

• Using \n inside single quotes expecting newline
• Missing quotes around text
• Trying to add strings with + operator