Script files and editor in MATLAB - Mini Project: Build & Apply

Script files and editor

📖 Scenario: You are learning how to use MATLAB script files and the editor to write and run simple programs.

🎯 Goal: Create a MATLAB script file that stores a number, calculates its square, and displays the result using the editor.

📋 What You'll Learn

Create a variable with a specific value

Create a second variable to store the square of the first

Use the MATLAB editor to write the script

Display the result using disp

💡 Why This Matters

🌍 Real World

Using script files in MATLAB helps automate calculations and data processing tasks.

💼 Career

Many engineering and scientific jobs require writing and running MATLAB scripts to analyze data and solve problems.

1

Create a variable in a script

Create a MATLAB script file and write a line that creates a variable called number and sets it to 7.

MATLAB

% Your code here

Hint

Use the assignment operator = to set number to 7.

2

Calculate the square

Add a line to the script that creates a variable called square and sets it to the square of number using the ^ operator.

MATLAB

number = 7;
% Your code here

Hint

Use square = number ^ 2; to calculate the square.

3

Display the result

Add a line to the script that uses disp to display the value of square.

MATLAB

number = 7;
square = number ^ 2;
% Your code here

Hint

Use disp(square); to show the result in the command window.

4

Run the script and see output

Run the script file in the MATLAB editor and observe the output. The output should be 49.

MATLAB

number = 7;
square = number ^ 2;
disp(square);
% Your code here

Hint

Run the script by pressing the Run button or typing the script name in the command window. The output should be 49.

Practice

1. What is the main purpose of a script file in MATLAB?

easy

A. To create graphical user interfaces

B. To save and run a group of commands together

C. To store variables permanently

D. To compile MATLAB code into an executable

Solution

1. Step 1: Understand what script files do

   Script files contain a sequence of MATLAB commands saved in a file to run together.

2. Step 2: Compare options with script file purpose

   Only To save and run a group of commands together describes saving and running commands together, which is the main use of scripts.

3. Final Answer:

   To save and run a group of commands together -> Option B

4. Quick Check:

   Script files = save and run commands [OK]

Hint: Scripts group commands to run all at once [OK]

Common Mistakes:

• Confusing scripts with functions
• Thinking scripts store variables permanently
• Assuming scripts compile code

2. Which of the following is the correct way to save a script file in MATLAB Editor?

easy

A. Click File > Save or press Ctrl+S

B. Type save script in the command window

C. Right-click the command window and select Save

D. Use the command saveas('filename') in the script

Solution

1. Step 1: Identify how to save files in MATLAB Editor

   The Editor uses standard save options like File menu or Ctrl+S shortcut.

2. Step 2: Evaluate each option

   Only Click File > Save or press Ctrl+S correctly describes saving via Editor menu or shortcut. Others are incorrect or commands for different purposes.

3. Final Answer:

   Click File > Save or press Ctrl+S -> Option A

4. Quick Check:

   Save script = File menu or Ctrl+S [OK]

Hint: Use File menu or Ctrl+S to save scripts [OK]

Common Mistakes:

• Trying to save scripts from command window
• Using saveas command incorrectly
• Right-clicking command window instead of Editor

3. What will be the output when running this script in MATLAB Editor?

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

medium

A. 8

B. 53

C. x + y

D. Error: Undefined variable

Solution

1. Step 1: Understand the script commands

   Variables x and y are assigned 5 and 3, then z is sum of x and y.

2. Step 2: Calculate the value of z and output

   z = 5 + 3 = 8, disp(z) prints 8 to the command window.

3. Final Answer:

   8 -> Option A

4. Quick Check:

   5 + 3 = 8 output [OK]

Hint: Add variables then display result [OK]

Common Mistakes:

• Concatenating numbers as strings
• Expecting variable names printed
• Assuming error without variable initialization

4. Identify the error in this MATLAB script:

for i = 1:3
  disp(i)
endd

medium

A. disp function used incorrectly

B. Missing semicolon after disp(i)

C. Loop variable i is not defined

D. Incorrect end keyword spelling

Solution

1. Step 1: Check the loop syntax

   The for loop uses 'endd' instead of 'end' to close the loop.

2. Step 2: Identify the syntax error

   MATLAB requires 'end' keyword exactly; 'endd' causes a syntax error.

3. Final Answer:

   Incorrect end keyword spelling -> Option D

4. Quick Check:

   Loop ends with 'end' keyword [OK]

Hint: Use exact 'end' to close loops [OK]

Common Mistakes:

• Typing 'endd' instead of 'end'
• Forgetting to close loops
• Adding unnecessary semicolons

5. You want to create a script that calculates the average of numbers stored in a vector data. Which script structure correctly computes and displays the average?

hard

A. avg = mean(data)
disp(total);

B. for i = 1:length(data)
avg = data(i) / length(data);
end
disp(avg);

C. total = sum(data);
count = length(data);
avg = total / count;
disp(avg);

D. avg = sum(data) * length(data);
disp(avg);

Solution

1. Step 1: Understand how to calculate average

   Average = sum of elements divided by number of elements.

2. Step 2: Check each script option

   total = sum(data);
   count = length(data);
   avg = total / count;
   disp(avg);

   correctly sums data, counts elements, divides, then displays average. Others have errors: A displays undefined total, C overwrites avg incorrectly in loop, D multiplies instead of dividing.

3. Final Answer:

   total = sum(data); count = length(data); avg = total / count; disp(avg); -> Option C

4. Quick Check:

   Average = sum / count [OK]

Hint: Average = sum divided by count, then display [OK]

Common Mistakes:

• Using mean without displaying correct variable
• Calculating average inside loop incorrectly
• Multiplying sum by length instead of dividing