CGI Group IOS Developer Interview Questions and Answers

Q1. What is Weak & Unowned , ARC?
Ans. 
Weak & Unowned references are used in ARC to prevent retain cycles in Swift programming.
• Weak references do not increase the retain count of an object, and automatically become nil when the object is deallocated.

• Unowned references do not keep a strong reference to the object, and can become a dangling pointer if the object is deallocated.

• ARC (Automatic Reference Counting) is a memory management system used in Swift to a
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Q2. What is Autoclosure?
Ans. 
Autoclosure is a feature in Swift that automatically wraps an expression in a closure.
• Autoclosure is used to delay evaluation of an expression until it is actually needed.

• It is commonly used with functions that take closures as arguments, allowing the caller to pass in a regular value instead of a closure.

• Autoclosures are created by adding @autoclosure attribute before the closure's parameter type.
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Q3. Code snippets for optional binding, find error ?
Ans. 
Optional binding in Swift helps to safely unwrap optionals and check for nil values.
• Use if let or guard let to safely unwrap optionals and bind the value to a new constant or variable.

• Check for nil values before using the unwrapped value to avoid runtime errors.

• Example: if let name = optionalName { print(name) }

• Example: guard let age = optionalAge else { return }
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Q4. What are Access Controls/modifiers? public vs open?
Ans. 
Access controls/modifiers determine the visibility and accessibility of classes, methods, and properties in object-oriented programming.
• public access control allows a class, method, or property to be accessed from anywhere in the code

• open access control allows a class to be subclassed outside of the module where it is defined

• public is commonly used in Swift for most cases, while open is used when you want to allow subc
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Q5. Protocol vs Closures?
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Protocols define a blueprint of methods, properties, and other requirements that a class or struct must adopt. Closures are self-contained blocks of functionality that can be passed around and used in your code.
• Protocols define a set of methods, properties, and other requirements that a class or struct must implement.

• Closures are self-contained blocks of functionality that can capture and store references to any consta...read more
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Q6. How you use GIT, How to manage conflicts?
Ans. 
I use GIT for version control and manage conflicts by resolving them through communication and collaboration.
• Regularly commit changes to keep track of progress

• Pull latest changes before making any updates to avoid conflicts

• Communicate with team members to resolve conflicts efficiently

• Use tools like Git merge or Git rebase to resolve conflicts

• Document resolution process for future reference
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Q1. Encription and decription in swift
Ans. 
Encryption and decryption in Swift involves using cryptographic algorithms to encode and decode data securely.
• Use common encryption algorithms like AES or RSA for encryption.

• Implement encryption using libraries like CommonCrypto or CryptoSwift.

• Store encryption keys securely and use secure protocols for data transmission.

• Example: Encrypting a string using AES encryption in Swift.
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Q2. Keychain access in swift
Ans. 
Keychain access in Swift allows secure storage of sensitive information like passwords, tokens, etc.
• Use Keychain Services API to securely store and retrieve sensitive data.

• Keychain items are stored securely in the device's keychain and are encrypted.

• Access keychain items using unique identifiers called keys.

• Use Keychain Swift library for easier implementation.
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Q3. Class vs struct
Ans. 
Classes are reference types, while structs are value types in Swift.
• Classes are reference types, meaning they point to the same instance in memory when assigned to a new variable.

• Structs are value types, meaning they create a new copy when assigned to a new variable.

• Use classes for complex data structures or when you need inheritance, use structs for simple data types or when you want value semantics.

• Example: class Per...read more
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Q4. If let and guard let
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Q5. Grand central dispatch in swift
Ans. 
Grand Central Dispatch (GCD) is a technology in Swift for managing concurrent operations.
• GCD allows developers to perform tasks concurrently without having to manage threads manually.

• It provides a high-level API for managing tasks and executing them on different queues.

• Developers can use GCD to perform tasks in the background, update the UI on the main thread, and more.
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Q1. Auto closures and Escaping closures
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Q2. Cardinality and string reverse coding
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Q1. Objective C vs swift
Ans. 
Objective-C is the older language used for iOS development, while Swift is the newer, more modern language.
• Objective-C is a superset of C with Smalltalk-style messaging syntax.

• Swift is more concise and easier to read than Objective-C.

• Swift is safer due to its optionals and type interference features.

• Objective-C has been around longer and has a larger codebase, but Swift is becoming more popular.

• Many developers prefer S...read more
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Q2. Autolayouts and content
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Q1. Difference betweenClass And Struct
Ans. 
Classes are reference types, while structs are value types in Swift.
• Classes are reference types, meaning they point to the same memory location when assigned to a new variable.

• Structs are value types, meaning they create a new copy when assigned to a new variable.

• Classes support inheritance, while structs do not.

• Classes can have deinitializers, while structs cannot.

• Classes can be typecasted, while structs cannot.
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Q2. Static Key work
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Find the index of the first occurrence in string

Q1. Salary Expectation
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Q2. Any leave plans in next six months
Ans. 
Yes, I have planned a vacation in the next six months.
• I have scheduled a week-long trip to Europe in September.

• I also plan to take a few days off around Christmas to visit family.

• I have informed my team in advance and ensured that my work will not be affected.
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Q1. What is closure? Life cycle of escaping closure?
Ans. 
A closure is a self-contained block of code that can be passed around and used in your code. An escaping closure is a closure that is called after the function it was passed to has returned.
• Closure is a block of code that can be passed around and used in your code.

• Escaping closure is called after the function it was passed to has returned.

• Example: Using a completion handler in a network request to handle the response a
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Q2. What is multi threading?
Ans. 
Multi threading is the ability of a CPU to execute multiple threads concurrently, allowing for improved performance and responsiveness in applications.
• Allows for parallel execution of tasks, improving performance

• Enables applications to remain responsive while performing intensive tasks

• Can lead to synchronization issues if not managed properly
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Q1. Basic questions related to Swift like closure, optionals, gcd, operations. Questions related to sdks like firebase, push notifications
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Q1. It was about the projects, methodologies used, architecture, roles and responsibilities in team.
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Q1. Singletone, multithreading, oops
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