Top 25 System Design Interview Questions And Answers
Following are frequently asked questions in interviews for freshers as well as experienced system designers.
1) What is System Design?
System design is a process of defining the elements of a system such as the architecture, components, modules, and various interfaces.
2) What are the three most essential skills of system designer?
Important skills for system designer are:
- User interaction
- Offline processes
3) How to design traffic control software?
To design a system for the traffic control system, as a software engineer, you need to make sure you know how to transition from one state to another. For example, Red to Green and from Green to Orange to Red, etc.
4) What is the benefit of a designing system like Pastebin?
Pastebin helps you design a system to paste code or text. You can share a link to that code anywhere you want. Its not an online code editor, yet you can use this, a tool to store any text.
5) As a system designer, how you can design a universal file sharing and storage apps like Google Drive or Dropbox?
The above mention apps are used to store and share files, photos, and other media. We can design things like allowing users to upload/search/view files or photos. It checks permissions for file sharing and enables multiple users to make changes in the same document.
6) How can you design an ATM system?
An ATM helps a user to deposit and withdraw money. It also allows users to see their account balance. You need to make a design plan to create this system.
What Is Nsurlconnection Class Define Its Types And Use Cases
There are two ways of using the NSURLConnection class. One is asynchronous and the other is synchronous.
An asynchronous connection will create a new thread and perform its download process on the new thread. A synchronous connection will block the calling thread while downloading the content and doing its communication.
Many developers think that a synchronous connection blocks only the main thread, which is not true. A synchronous connection will always block the thread from which it is fired. If we fire a synchronous connection from the main thread, the main thread will be blocked. However, if we fire a synchronous connection from a thread other than the main thread, it will be like an asynchronous connection and wont block our main thread.
In fact, the only difference between synchronous and asynchronous connections is that at runtime a thread will be created for the asynchronous connection while it wont do the same for a synchronous connection.
In order to create an asynchronous connection, we need to:
If you have any doubts or queries related to iOS, get them clarified from iOS experts on our iOS Community
Whats Your Understanding Of Ui Design
This question was highly asked in the interview process, I used to recite the definition of UI design and user interface design principles without missing a single word. However, they seem all failed. For me with no experience in UI design, they refused me for I even didnt really know what UI design is about. Then I learned this is absolutely not a definition on explaining question, what really matters is to add your personal views towards UI design. But the precondition is you must understand what UI design is pretty well.
You May Like: How To Track Exit Interview Data
What Is Enum Or Enumerations In Swift
The term enumeration refers to a user-defined data type consisting of a set of related values that allows you to work with those values in your code in a type-safe manner. An enumerated data type is defined by the keyword enum.
Syntax:
enum enum_name
Example:
enum MonthsofaYear
Values defined in an enumeration MonthsofaYear such as January, February, and so on until December are its enumeration cases. New enumeration cases can be introduced using the case keyword. You can put multiple cases on a single line, separated by commas as follows:
enum MonthsofaYear
Until You’ve Mastered These 50 Questions
Glassdoor has a page dedicated to Apple, and individuals who have interviewed at Apple give a review on their experience. This often includes specifics as to what problems, or at least, what types of problems they were asked during their interview.
After parsing through over one hundred interview experiences from Glassdoor for Apple, I obtained the following distribution of the types of problems that were generally encountered in an Apple interview.
For a bit more granularity, I also took these larger categories and broke them down into smaller subcategories. For instance, instead of grouping Graphs/Trees together into one item, I broke it down into more specific and separate Graphs and Trees categories. The corresponding graph is shown below:
From both of these graphs, its clear that Apple really favors the following topics:
- Linked List
- Arrays/String
- System Design
Protip: Apple generally only asks system design questions to candidates with at least 3-5 years of software engineering experience.
One of the observations I made in parsing through this data is that there were recurrent specific problems and topics that arose in all three of these subcategories.
Lets break each of these down. That way, youll be able to focus on the most likely categories, as well as the most likely specific problems, you may encounter in an Apple interview.
You May Like: How To Pass An Interview
Answer Ux Designer Interview Questions Through Your Portfolio
Never attend a job interview without a UX portfolio! Even if the company is not asking you to bring your portfolio, you should have it prepared. As you have seen with some of the UX designer interview questions above, examples are the best at proving a point.
If you want to stay organized, bring your computer or laptop to the interview and show your work through your digital portfolio. This way, you can be sure about narrating the process with precision. UXfolios case study templates will help you to showcase your design process in the best way. Answering the guiding questions and using our text examples will also help you to prepare for the interview.
Start building your portfolio easily, without coding, with UXfolio!
Why Design Patterns Are Important Name Some Of The Popular Design Patterns Used In Ios
A design pattern is a solution to a specific problem you might encounter while designing an app’s architecture. They are templates designed to make coding easier and more reusable for you. Following are some of the design patterns that can be used in iOS:
MVC : MVC is a design pattern for developing web applications in which three components are connected i.e., view, controller, and model. Views can be conceived as the user interface shown to the end-user at a certain point in time. The model represents the data to be shown on the view. The controller acts as a link between view and model. There is always a relationship between these three components.
MVVM : Unlike MVM, there is a special layer in MVVM called the View Model between the View and the Model. Using a view model, model information can be transformed into values that can be displayed on the view. There is a binding link between the view and View model that allows the view model to share updates with the view.
Facade: The facade design pattern provides a simplified interface to a complex set of classes, libraries or frameworks. As opposed to providing the user with a set of classes and their APIs, you instead provide a simple, unified API. While Facade helps to reduce overall application complexity, it also helps to move unwanted dependencies to a single location.
Don’t Miss: What Are Frequently Asked Questions In A Job Interview
What If Your Client Think Your Product Failed To Meet Their Requirement
Make it a chance to show how you could use user feedback to improve your work, also mention the importance to do through user research. Describe the detail to settle the conflict and how it finally works. Show your ability to communicate with people and deal with user misunderstanding. Moreover, demonstrate your listening skill, you can think a moment before you answer the question.
Describe Managed Object Context And Its Function
A managed object context is a temporary scratchpad in an application for a related collection of objects. These objects collectively represent an internally consistent view of one or more persistent stores.
A single-managed object instance exists in one and only one context, but multiple copies of an object can exist in different contexts.
The key functions of the managed object context include the following:
- Life-cycle management: Here, the context provides validation, inverse relationship handling, and undo/redo.
- Notifications: It refers to context posts notifications at various points that can be optionally monitored elsewhere in our application.
- Concurrency: Here, the Core Data uses thread confinement to protect managed objects and managed object contexts.
Read Also: How To Have Good Interview Skills
How Is The Apple Interview Different From Other Companies Interviews
The Two Against One style of interviewing is somewhat unique amongst the FAANG companies. This style is what it sounds like in that you are being interviewed by two Apple employees.
Outside of that though, the content you will encounter here will be very familiar to you, especially if you have read up on the other posts here on Byte by Byte that cover the and the .
Another difference may be in the enthusiasm that Apple employees have for their products. While its not mandatory, being an enthusiast and user of Apple products is a soft prerequisite. Of course, it wont be a make or break a thing if you are not, but it will probably raise a few eyebrows if youre enthusiastically against Apple products.
How Would You Design Twitter
Dont jump into the technical details immediately when you are asked this question in your interviews. Do not run in one direction, it will just create confusion between you and the interviewer. Most of the candidates make mistakes here and immediately they start listing out some bunch of tools or frameworks like MongoDB, Bootstrap, MapReduce, etc. Remember that your interviewer wants high-level ideas about how you will solve the problem. It doesnt matter what tools you will use, but how you define the problem, how you design the solution, and how you analyze the issue step by step.
You can put yourself in a situation where youre working on real-life projects. Firstly, define the problem and clarify the problem statement. In this question, we will compress Twitter to its MVP . Nobody expects you to design the whole service. So, we will only design the core features of Twitter instead of everything.
Recommended Reading: What Makes You A Good Leader Interview Answer
What Do You Mean By Deep Linking In Ios
Deep links are links that send users directly to an app directly instead of a website or store using URI or universal links. The URL scheme is a well-known method of having deep links, but Universal Links are Apple’s new approach to connecting your web page and your app under the same link. Deep linking involves not only creating a clickable link that opens up your app, but also a smart one that navigates to the resource you desire. Users are directed straight to in-app locations using these links, which saves them the time and effort of finding those pages themselves thus improving their user experience tremendously.
Explanation: If you use the URL fb://, you may open the Facebook app. However, if you use fb://profile/33138223345, you will open Wikipedia’s profile in the Facebook app.
Over 150 Ios Interview Questions
If you’re a Swift developer preparing for your next job interview, this page is perfect for you: I’ve collected over 150 of the top interview questions about iOS, Swift, UIKit, SwiftUI, and more, and also provided suggested approaches to answering each question.
These questions are used by companies around the world in their interviews. Not questions “like these” or “based on these” companies literally use these exact questions. So, browsing through a few and testing yourself is a great way to prepare.
Questions are grouped by category, and I’ve also tried to provide some idea of difficulty using a traffic light system. Obviously my idea of “easy” or “hard” won’t exactly match yours, but hopefully it at least lets you focus your attention more easily. To get started, select a category, then select a question that interests you.
Tip: For more kinds of interview preparation and career guidance, see my Swift Career Guide.
Also Check: How To Answer System Design Interview Questions
Explain Swifts Pattern Matching Techniques
- Tuple patterns: Values of corresponding tuple forms are matched using tuple patterns.
- Type-casting patterns: You can cast or mix styles using type-casting patterns.
- Wildcard patterns: Every kind and kind of value is matched by wildcard patterns, which disregard them.
- Optional patterns: To align optional values, optional patterns are used.
- Enumeration case patterns: The cases of existing enumeration forms are matched by enumeration case patterns.
- Expression patterns: You may use expression patterns to compare a given value to a given expression.
What Are The Features Added In Ios 9
The following features are added in iOS 9:
- Intelligent search: It is an excellent mechanism to learn user habits and act on that informationopen apps before we need them, make recommendations on places we might like, and guide us through our daily lives to make sure were where we need to be at the right time.
- Siri: It is a personal assistant to the users that is able to create contextual reminders and search through photos and videos in new ways. Swiping right from the home screen brings up a new screen that houses Siri Suggestions, putting favorite contacts and apps right on our fingertips, along with nearby restaurant and location information and important news.
- Deeper search capabilities: It can show results such as sports scores, videos, and content from third-party apps, and we can even do simple conversions and calculations using the search tools on our iPhone or iPad.
- Performance improvements: The following built-in apps have been improved:
- Notes including new checklists and sketching features
- Maps now offering transit directions
- Mail allowing for file attachments
- New News app that learns our interests and delivers relevant content we might like to read
- Apple Pay being improved with the addition of store credit cards and loyalty cards
- Passbook being renamed to Wallet in iOS 9
Recommended Reading: What Are Some Questions You Should Ask In An Interview
A Simple Framework For Mobile System Design Interviews
The list of posts in this series:
- Part 1: A Simple Framework For Mobile System Design Interviews
- Part 7: Common Interview Mistakes
Below is a simple framework for Mobile System Design interviews. As an example, we are going to use the Design Twitter Feed question. The proposed solution is far from being perfect but it is not the point of a system design interview round: no one expects you to build a robust system in just 30 min the interviewer is mostly looking for specific signals from your thought process and communication. Everything you say should showcase your strengths and help the interviewer to evaluate you as a candidate.
How Can You Respond To State Transitions On Your App
State transitions can be responded to state changes in an appropriate way by calling corresponding methods on the apps delegate object.
For example:
- applicationDidBecomeActive method: To prepare to run as the foreground app
- applicationDidEnterBackground method: To execute some code when the app is running in the background that may be suspended at any time
- applicationWillEnterForeground method: To execute some code when the app is moving out of the background
- applicationWillTerminate method: Called when the app is being terminated
Don’t Miss: What To Ask In An Interview As A Candidate
How To Pass The Apple Interview: A Practical Guide
Are you a Mac enthusiast? Do you find yourself gravitating toward the sleek and elegant designs of the various and ubiquitous Mac products?
Perhaps you saw Steve Jobs Harvard commencement speech and gained a new respect for the Apple company. Or maybe you are more oriented toward the engineering aspects of Apple and marvel at how Wozniak was able to put together the original Apple II?
Whether you are an Apple fanboy, a Mac user, or just an enthusiast, the philosophy behind the company is one that many want to be a part of and identify with. Perhaps owning an Apple product and being part of the so-called Apple family is not quite enough, and you desire to play a role in the developer ecosystem of Apple.
Working for Apple also has many of the same benefits enjoyed from working at any of the other large tech companies, including , , , etc: high salary, free food, Apple swag, prestige, among many others.
Whatever your path for desiring to work at Apple, this post will be a one-stop shop for constructing your strategy to dominate the Apple Interview.
What Is The Purpose Of Reuseidentifier What Is The Benefit Of Setting It Into A Non
The reuseIdentifier is used to group together the similar rows in a UITableView, i.e., the rows that differ only in their content, otherwise having similar layouts. A UITableView will normally allocate just enough UITableViewCell objects to display the content visible in the table.
If reuseIdentifier is set to a non-nil value, then the UITableView will first attempt to reuse an already allocated UITableViewCell with the same reuseIdentifier when the table view is scrolled. If reuseIdentifier has not been set, then the UITableView will be forced to allocate new UITableViewCell objects for each new item that scrolls into view, potentially leading to laggy animations.
Don’t Miss: How To Prepare For Full Stack Developer Interview
