Dart Questions and Answers for Viva

Answer-1: Dart is an open-source, object-oriented programming language optimized for building web, mobile, and server applications.

Answer-2: Dart was developed by Google.

Answer-3: Dart is mainly used for building Flutter applications for web, mobile, and desktop platforms.

Answer-4: Key features include object-oriented programming, a sound type system, async/await for concurrency, and a modern standard library.

Answer-5: The Dart SDK includes tools such as the Dart VM, the Dart compiler, and core libraries for writing and running Dart programs.

Answer-6: Dart is optionally typed, meaning it supports both static and dynamic typing.

Answer-7: Dart's core data types include int, double, String, bool, List, and Map.

Answer-8: var is used to declare variables with inferred types.

Answer-9: final variables are initialized once, while const variables are compile-time constants.

Answer-10: Use the class keyword. Example: class MyClass {}.

Answer-11: Use the new keyword (optional). Example: var obj = MyClass();.

Answer-12: A constructor is a special method used to initialize objects of a class.

Answer-13: Named constructors are additional constructors in a class defined using a ClassName.name syntax.

Answer-14: Getters retrieve values, and setters modify them. Example: get name => _name; set name(value) => _name = value;.

Answer-15: Use List. Example: var myList = [1, 2, 3];.

Answer-16: Use Map. Example: var myMap = {'key1': 'value1', 'key2': 'value2'};.

Answer-17: A mixin is a class used to share behavior among multiple classes without inheritance.

Answer-18: Use the mixin keyword. Example: mixin MyMixin {}.

Answer-19: An abstract class cannot be instantiated and is used as a blueprint for other classes.

Answer-20: Use try, catch, on, and finally blocks. Example: try { } catch (e) { }.

Answer-21: Asynchronous operations are non-blocking and handled using Future and async/await.

Answer-22: A Future represents a value that will be available at a later time.

Answer-23: The async keyword is used to define an asynchronous function.

Answer-24: await pauses execution of an async function until the awaited Future completes.

Answer-25: Use the void keyword for no return or specify a return type. Example: void myFunction() { }.

Answer-26: Parameters in Dart can be optional and are defined with square brackets [] or curly braces {}.

Answer-27: A Stream provides a sequence of asynchronous data events.

Answer-28: await for is used to iterate over asynchronous data streams.

Answer-29: Null safety ensures that variables cannot contain null unless explicitly declared as nullable.

Answer-30: Nullable types are denoted with a ?. Example: String? nullableString;.

Answer-31: assert is used for debugging, to check boolean conditions during development.

Answer-32: The main() function is the entry point of every Dart program.

Answer-33: pub is Dart's package manager used to manage libraries and dependencies.

Answer-34: Use the import keyword. Example: import 'dart:math';.

Answer-35: Isolates are independent threads of execution with no shared memory, used for concurrency.

Answer-36: Use a private constructor and a static instance. Example: class MySingleton { static final MySingleton _instance = MySingleton._(); MySingleton._(); }.

Answer-37: static defines members that belong to the class rather than an instance.

Answer-38: == checks value equality, while identical() checks if two objects are the same instance.

Answer-39: The is operator checks the type of an object. Example: if (obj is String) { }.

Answer-40: typedef is used to define function type aliases. Example: typedef IntFunction = int Function(int);.

Answer-41: The map method transforms a list into a new list by applying a function to each element.

Answer-42: Use final fields and a constant constructor. Example: class Immutable { final int value; const Immutable(this.value); }.

Answer-43: List allows duplicates and maintains order, while Set contains unique elements with no guaranteed order.

Answer-44: Dart's core library provides basic functionalities like numbers, strings, collections, and exceptions.

Answer-45: sync* is used for synchronous generators, and async* is used for asynchronous generators.

Answer-46: dynamic is a type that can hold any value, with type checks deferred until runtime.

Answer-47: Generic types enable classes and methods to operate on different data types. Example: List.

Answer-48: The operator keyword allows you to override operators for custom classes.

Answer-49: Use the dart:convert library's json.encode() and json.decode() methods.

Answer-50: rethrow is used to propagate caught exceptions. Example: catch (e) { rethrow; }.