## Introduction

MATLAB is an abbreviation for Matrix Laboratory. It is a multi-paradigm programming language for numerical computing. It is an environment developed by MathWorks. It allows the plotting of data, matrix manipulations, and program implementation. It is an easy-to-understand language where the outputs are in binary notation. Matlab Interview Questions are an important part of any software engineering interview.

MATLAB is a high-in-demand language frequently asked in interviews, especially in software engineering and data science. This blog discusses the Matlab interview questions according to the difficulty level.

**Most Asked Matlab Interview Questions and Answers**

**1. What do you understand by MATLAB API?**

The MATLAB data API allows the applications not written in MATLAB to interact with MATLAB-driven applications. It will enable us to make API Calls and access the resources.

**2. Discuss memory management functions in MATLAB.**

Memory management is used to manage the resources of a computer. The memory is assigned whenever an application is running and freed when the work is done. The following functions are prominent in MATLAB-

Clear- It removes the memory occupied by the variable.

Pack- It saves the existing variables and reloads them on demand.

Load- It reloads the data previously saved.

Save- It simply saves the data.

Quit- It exits and frees the memory occupied by MATLAB.

**3. What are M-Files and MEX files?**

M-Files are ASCII scripts. They are interpreted at the run-time. They have a significant role to play in the development of MATLAB. These are also platform-independent.

MEX Files are written in C or C++. They are joined with the MATLAB files at the run-time.

**4. How do we perform Stress Analysis in MATLAB? **

Stress Analysis using MATLAB is usually performed in aerospace and space environments.

NASTRAN, Oracle, and IDEAD levels of proficiency are essential to analyze stress.

**5. Explain the concept of Loops in MATLAB.**

While Loop- Continues to repeat a statement while a given condition is true.

For Loop- Executes multiple times until a condition is satisfied.

Nested Loop- You can use loops inside other loops.

**6. Discuss XMath in detail. **

X-Math is an interactive scripting tool widely used in MATLAB. The features present in X-Math are-

Object-oriented Programming Features

Compatible Libraries with C and LNX

Debugging facility with extensive Graphical User Interface.

**7. How is code commented in MATLAB? **

Comments are written in code to make understanding easier.

The syntax is -

`â€ś % Welcome to Coding Ninjas. â€ť`

###

**8. How do we plot graphs in MATLAB? **

The following functions allow the user to plot graphs-

**Box:**Border of Axis**Errorbar:**Constructs error bars.**Hold:**Preserves the current graph while adding a new one.**Line:**Creates a line.**Plot:**2-D Line Plot.**Plot3:**3-D Line Plot.**Xlim:**Defines x-axis limits.**Ylim::**Defines y-axis limits.**Zlim:**Defines z-axis limits.

You can also read, __Power Apps Interview Questions__

###

**9. How to handle images and graphics in MATLAB?**

MATLAB provides extensive features for graphics modification. Both high-level and low-level commands are present. The low-level controls allow us to create GUI from scratch and make changes. At the same time, the high-level commands will enable us to process images, visualize data and perform animations.

**10. Write a code to work with the matrix in MATLAB.**

`a = [ 11 12 13 14 ; 12 13 14 15 ; 13 14 15 16 ; 14 15 16 17 ]`

This is a method to create a 4X4 Matrix. The output will look like this-

a =

11 12 13 14

12 13 14 15

13 14 15 16

14 15 16 17

**11. What is Classification accuracy? How do we calculate it?**

Classification Accuracy means the count of the data which is correctly classified. This is how we can perform Accuracy Calculations in MATLAB-

```
% out= evalfis( fis, in);
p = round(out);
acc_count = nnz( p==in);
acc = acc_count/length(in);
```

###

**12. What is Simulink in MATLAB? **

Simulink is an additional product in MATLAB. Users can use it to provide a graphical and interactive environment to analyze dynamic models.

**13. What do you mean by Interpolation and Extrapolation? **

Extrapolation means determining the value of an unknown quantity that is not clearly stated by the current information.

Interpolation, on the other hand, means estimating a value with the help of two given values.

**14. What are housekeeping functions? Mention their significance. **

Housekeeping functions are the ones that do not play a vital role in Mathematics but come in handy while programming.

Some examples of Housekeeping functions are as follows-

```
ceil(x)
fix(x)
floor(x)
length(a)
mod(x,y)
rem(x,y)
```

###

**15. What are neural networks, and how are they used in MATLAB? **

A neural network is a replica of the human brain. A neural network learns from previously available information and can be trained to recognize patterns, classify, and predict trends.

MATLAB toolbox provides apps and command line functions to allow working with neural networks. After generating the neural networks, users can automatically create MATLAB code for performing operations like regression, clustering, time series analysis, etc.

**16. Explain the â€śFuzzy Logicâ€ť toolbox. **

The fuzzy Logic toolbox provides MATLAB functions and ease of access. It allows analyzing, plotting, and simulating systems based on fuzzy logic. It performs the above tasks using a Simulink block. The toolbox makes it easy for users to interpret complex models using simple reasons.

**17. How can we visualize 3-D elements in MATLAB? **

MATLAB can handle 3-D visualization with the following features-

**Lighting **Users can add and control scene lighting.

**Transparency** It is used for the determination of object transparency.

**Volume Visualisation **It determines the volumes of the grid.

**Surface and Mesh Plots **It handles plotting, matrices, and color maps.

**18. Which programs are allowed in MATLAB?**

MATLAB permits Scripts and Functions.

- Scripts: It is a file saved with a .m extension. It doesnâ€™t accept inputs and doesnâ€™t return any outputs.
- Functions: The functions can accept input and return sound outputs.

###

**19. How to read a CSV file in MATLAB?**

CSV means Comma Separated Values. In the previous versions of MATLAB csvread command was used. In the newer versions, it has been replaced by a readmatrix.

Syntax:

`CN= readmatrix(filename)`

###

**20. What is the procedure for creating a GUI in MATLAB?**

- Select
**File**>**Preferences**>**GUIDE**. - Select the â€ś
**Show namesâ€ť feature in the component palette**.

Following the above steps, The user can create a GUI in MATLAB.

**21. Explain the TEXTREAD function in MATLAB.**

It allows you to read the text with flexibility. There is an option of ignoring comments, skipping lines at the start, and other additional features.

**22. What is the basic idea behind solving differential equations in MATLAB?**

The differential equations can be solved using proper mathematics and syntax. For greater accuracy, we use some ode solvers, namely ode23, ode45, ode15s, and ode23s.

Syntax-

`[t, y] = ode45(@Name_of_function, tspan, n0)`

###

**23. How are polynomials expressed in MATLAB?**

Polynomials are equations of a single variable with different components.

For example, [1 -3 2] corresponds to x2 â€“ 3x + 2. Some of the functions are:

Poly, polyeig, polyfit, residue, roots, polyval, etc.

**24. What is the difference between * and .* in MATLAB?**

- * is a vector or matrix multiplication; the operands should follow the rules of matrix multiplication in this case.
- .* is an element-wise multiplication. Matrix size should be equal to carry out this operation.

###

**25. Why are Categorical Arrays more beneficial than Character Arrays?**

Categorical arrays are more memory efficient than character arrays. Unlike, Character arrays that allow just alphabetical ordering, they offer precise mathematical arrangement.

In categorical arrays, we can make comparisons easily by using (==), while we need to use strcmp to compare in character arrays.

**26. What do you mean by set and get functions in MATLAB?**

Set means setter function. It is used to appoint properties in MATLAB.

Get stands for getter function. It is used to obtain properties in MATLAB.

**27. What is the main difference between regular and cell arrays?**

In simple language, regular arrays contain the same elements; in cell arrays, the parts are heterogeneous, that is, different elements.

Cell Arrays are used when-

- We have different types in your array.
- We are not sure whether you might extend it to another type in the future.
- We are working with objects that have an
*inheritance pattern*.

Regular Arrays are used when-

- We have the same type of elements.
- We will not change the data type of the array in the future.
- We are working with objects that have
*no inheritance*.

###

**28. What is the purpose of P-code?**

P-code files are executable obscured files. It gives the feature of hiding the source code from others. P-code is platform independent as well.

**29. What are the methods to secure your code in MATLAB?**

**Transform it to P-Code**- Converting the code to p-code increases security as the code is hidden from others. You can convert a few lines of code or a significant chunk of code to a P-code document (.p extension).

**Accumulate into a double solution**- You can use MATLAB compiler to compile your source code and create an independent application.

**30. How many breakpoints are there in MATLAB? Explain.**

- Standard Breakpoint: F12 key is used to pause the program's execution according to the user's will.
- Conditional Breakpoint: The program stops execution only where a specific condition is met.
- Error Breakpoint: The program pauses its execution when it encounters an error situation.