First MATLAB program - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple MATLAB script

What is the output of this MATLAB code when run in the command window?

MATLAB

x = 5;
y = 3;
z = x + y;
disp(z);

A x + y

B 8

C 53

D Error: Undefined function or variable 'z'.

💡 Hint

Remember that disp shows the value of the variable, not the expression.

The code adds x and y (5 + 3) and stores in z, then displays z, which is 8.

🧠 Conceptual

intermediate

Understanding MATLAB script execution

Which statement best describes what happens when you run a MATLAB script file?

A MATLAB executes commands line by line in the script from top to bottom.

B MATLAB compiles the script into a standalone program before running.

C MATLAB runs all commands in the script simultaneously.

D MATLAB only checks the script for syntax errors but does not run it.

💡 Hint

Think about how you read a recipe or instructions.

MATLAB runs scripts line by line in order, executing each command sequentially.

🔧 Debug

advanced

Identify the error in this MATLAB code

What error will this MATLAB code produce when run?

MATLAB

a = 10
b = 20;
c = a + b;
disp(c);

A No error, output is 30

B Syntax error: Missing semicolon after first line

C Runtime error: Undefined variable 'a'

D Syntax error: Missing end statement

💡 Hint

In MATLAB, semicolons suppress output but are not required for correctness.

MATLAB allows lines without semicolons; it will display the value of 'a' but no error occurs.

❓ Predict Output

advanced

Output of a MATLAB script with string and numeric variables

What will be displayed when this MATLAB code runs?

MATLAB

name = 'Alice';
age = 25;
message = [name, ' is ', num2str(age), ' years old.'];
disp(message);

A Alice is age years old.

B Error: Cannot concatenate string and number directly.

C Alice is 25 years old.

D Alice is 25 years old

💡 Hint

num2str converts numbers to strings for concatenation.

The code converts age to string and concatenates with name and other text, then displays the full message.

🚀 Application

expert

Number of elements in a MATLAB array after operations

Consider this MATLAB code. How many elements does the variable 'result' contain after execution?

MATLAB

arr = 1:10;
result = arr(arr > 5);

A 6

B Error: Logical indexing not allowed

C 10

D 5

💡 Hint

Think about which numbers in arr are greater than 5.

arr > 5 is true for elements 6,7,8,9,10, so result contains 5 elements.