MATLAB Vectors
Dynamic Memory & Preallocation
Signal Processing Basics
MATLAB Structures & Data
File I/O and Integration
100
What command turns a row vector into a column vector?
x' or transpose(x)
100
What MATLAB function can be used to initialize a vector with undefined values?
NaN or zeros or ones (for init)
100
What is the MATLAB command to generate a 10 Hz sine wave over 1 second?
t = 0:0.01:1; x = sin(2*pi*10*t);
100
What command creates a structure with fields: name, score, and pass?
struct('name','A','score',90,'pass',true)
100
What MATLAB function would you use to read a numeric .txt file with a single column?
readmatrix or load
200
What happens if you perform x + y when x is a 1×5 vector and y is a 5×1 vector?
Dimension mismatch error (1×5 + 5×1 not valid for element-wise ops)
200
Why is growing a vector inside a loop discouraged?
MATLAB reallocates memory every iteration, slowing execution
200
How does plot() differ from stem() in signal visualization?
plot draws lines, stem shows discrete points
200
How do you access the third student’s GPA in a structure array named students?
students(3).GPA
200
What does writematrix(data, 'output.txt') do?
Saves numeric array to output.txt
300
Explain why length() may not be sufficient for checking matrix size in 2D arrays.
length() only returns the largest dimension, not all dims like size()
300
Write a script snippet to preallocate a 1000-element column vector of ones
A = ones(1000, 1);
300
Why does undersampling cause a misrepresentation of the signal frequency?
Undersampling causes high frequencies to appear lower (aliasing)
300
Write a loop to display all student names who have graduated == true.
for i=1:length(students), if students(i).graduated, disp(...), end
300
Name two reasons C++ outputs must be cleaned before being imported into MATLAB.
Quotes and commas cause parsing errors in readtable/str2num
400
True or False: zeros(3,1) preallocates a row vector. Justify your answer.
False – zeros(3,1) creates a column vector, not row
400
Compare runtime performance of a loop with vs. without preallocation using tic and toc.
Use tic, run loop with/without preallocation, then toc
400
Given t = 0:0.01:1;, what is the effective sampling frequency?
1 / 0.01 = 100 Hz
400
What data structure would you use to store mixed signal packets of strings and numbers?
Cell array — supports mixed data types
400
Write a one-line MATLAB command to read a file called average_results.txt and plot the value.
bar(readmatrix('average_results.txt'))
500
Given v = [5 10 15 20], write a line of code to double only the values greater than 10.
v(v > 10) = v(v > 10) * 2;
500
Identify the logical error:
No error, but should preallocate: A = zeros(1,1000); first
500
Modify a sine wave signal to simulate Gaussian noise using built-in MATLAB functions.
signal_noisy = signal + 0.2 * randn(size(signal));
500
Define a nested structure for a robotic joint that includes position and a motor substructure.
500
Describe a real-world engineering reason to connect C++ pre-processing with MATLAB visualization.
C++ is faster at preprocessing; MATLAB is better for visualization