Script files and editor in MATLAB - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple script file

What is the output when you run this MATLAB script file named example.m?

MATLAB

a = 5;
b = 3;
c = a + b;
disp(c);

A 8

B 53

C a + b

D Error: Undefined function or variable 'c'.

💡 Hint

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

The script adds 5 and 3, stores in c, then displays c, which is 8.

❓ Predict Output

intermediate

Variable scope in script files

Given this script myscript.m:

a = 10;
b = 20;
c = a + b;

What will be the value of c in the MATLAB command window after running myscript?

MATLAB

a = 10;
b = 20;
c = a + b;

A 0

B 30

C Error: Variable 'c' is undefined.

D 30 but only inside the script, not in the command window.

💡 Hint

Script files share the workspace with the command window.

Variables created in scripts appear in the base workspace and can be accessed after running the script.

🔧 Debug

advanced

Identify the error in this script

What error will MATLAB show when running this script file named test.m?

MATLAB

x = 5
if x > 3
    disp('x is greater than 3');
end

A No error, output: x is greater than 3

B Syntax error: Missing semicolon after first line

C Syntax error: Missing 'end' for if statement

D Runtime error: Undefined variable 'x'

💡 Hint

In MATLAB, semicolons are optional to end statements.

MATLAB allows statements without semicolons; the if block is correctly closed with 'end'.

❓ Predict Output

advanced

Effect of clearing variables in script

Consider this script clear_test.m:

clear
x = 7;
y = x * 2;
disp(y);

What will be the output when you run clear_test?

MATLAB

clear
x = 7;
y = x * 2;
disp(y);

A 0

B Error: Undefined variable 'x'.

C 14

D No output, script clears all variables and stops.

💡 Hint

The clear command removes variables before new ones are created.

The script clears variables, then assigns x=7, y=14, and displays 14.

🧠 Conceptual

expert

Script file behavior with function definitions

What happens if you define a function inside a MATLAB script file and then call it within the same script?

MATLAB

disp(myfunc(3));

function y = myfunc(x)
    y = x^2;
end

A Error: Functions cannot be defined inside script files

B The script runs but outputs nothing

C Error: Function 'myfunc' is undefined when called

D The script runs and outputs 9

💡 Hint

Since MATLAB R2016b, local functions can be included in scripts.

Modern MATLAB allows local functions in scripts; calling them works and outputs 9.