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Dart Programming Articles
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Iterator class in Dart Programming
Iterator class in Dart is an interface that is used when we want to get items, one at a time, from an object.The iterator is initially positioned before the first element. Before accessing the first element the iterator need to be advanced using the moveNext to point to the first element. If we reached the end of the object then moveNext returns false, and all further calls to moveNext will also return false.It should be noted that if change anything in the object during the iteration, then the behaviour is unspecified.We make use of the current property of the Iterator ...
Read MoreLexical Scoping in Dart Programming
Dart is a lexically scoped language. Lexically scoped means that as we move downwards to the latest variable declaration, the variable value will depend on the innermost scope in which the variable is present.ExampleConsider the example shown below −void main(){ var language = 'Dart'; void printLanguage(){ language = 'DartLang'; print("Language is ${language}"); } printLanguage(); }In the above example, we changed the value of the language variable inside the scope of the printLanguage() function and since we are printing the value inside the printLanguage() function, the innermost scope is the one inside the ...
Read MoreMethod Overriding in Dart Programming
We know that we can access the methods that are present in the superclass from a subclass by making use of the super keyword or by simply creating objects of the subclass. Though, there may be different occasions when we want the subclass object to do things differently to the same method when invoked using subclass objects. We can achieve this by defining the same method again in the subclass with the same name, same arguments and same return type as in the same method that is present inside the superclass.Now, when we invoke that method, the method present in ...
Read MoreMethods in Dart Programming
A method is a combination of statements which is used to attach some behavior to the class objects. It is used to perform some action on class objects, and we name methods so that we can recall them later in the program.Methods help in making the core more modular and in increasing the re-usability of the program.Information can be passed to methods through the parameters and then it can perform some operation on that information or it can even return values.Methods in a class are of two types, these are −Instance methodsClass methodsInstance MethodsInstance methods are methods that are present ...
Read MoreMixins in Dart Programming
Mixins in Dart are a way of using the code of a class again in multiple class hierarchies. We make use of the with keyword followed by one or more mixins names.Mixins can be used in two ways, the first case is when we want to make use of class code in such a way that the class doesn't have any constructor and the object of the class is extended. In such a case, we use the with keyword.Another case is when we want our mixin to be usable as a regular class, then we make use of the mixin keyword ...
Read MoreRead and Write Input in Dart Programming
Dart provides us with a standard library named 'io' which contains different classes and in turn, these classes contains different methods that we can use to read or write input from the terminal.We import the library in our program by making use of the import command.ExampleConsider the example shown below −Import 'dart:io';Writing something to the terminalWe can write something to the terminal by making use of the standard out class (stdout) that is available to us in the 'dart:io' library.ExampleConsider the example shown below −import 'dart:io'; void main(List arguments) { stdout.write('What is your name?\r'); }OutputWhat is your name?Note − ...
Read MoreReturn statement in Dart Programming
There are certain cases where we want to return a value from a given function so that we can use it later. These return values make use of a return keyword which in turn allows a function to return values.It should be noted that the return statement is optional, if not specified the function returns null.Also, only one return statement is allowed in a function.Syntaxreturn ;Syntax of a Dart function with a return value −returnType funcName(){ // statement(s) return value; }In the above syntax, the funcName is replaced with the name of our function. The returnType represents the type of data/expression ...
Read MoreString Interpolation in Dart Programming
There are times when we want to make use of variables inside the statement that is made up of string values.We know that we can add two strings together in Dart with the help of the + symbol operator. But to make use of a variable in between the strings that we are concatenating, we need to add one more + symbol and then type the name of the variable, which works okay when it comes to small statements.ExampleConsider the example shown below −void main(){ String name = "Tutorials"; var collegeName = "DTU"; print("Name is " + ...
Read MoreSuper constructor in Dart Programming
The subclass can inherit the superclass methods and variables, but it cannot inherit the superclass constructor. The superclass constructor can only be invoked with the use of the super() constructor.The super() constructor allows a subclass constructor to explicitly call the no arguments and parametrized constructor of superclass.SyntaxSubclassconstructor():super(){ }Though, it is not even necessary to use the super() keyword as the compiler automatically or implicitly does the same for us.When an object of a new class is created by making use of the new keyword, it invokes the subclass constructor which implicitly invokes the parent class's default constructor.Let's make use of an example where ...
Read MoreSuper keyword in Dart Programming
Super keyword in dart is used to refer to the parent's class object's methods or variables. In simple terms, it is used to refer to the superclass properties and methods.The most important use of the super keyword is to remove the ambiguity between superclass and subclass that have methods and variables with the same name.The super keyword is able to invoke the parent's objects method and fields, as when we create an instance of the subclass in Dart, an instance of the parent class is also created implicitly.Syntaxsuper.varName or super.methodNameAs we can access both the variables and methods of the parent's ...
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