We know that strings in Dart are a sequence of Unicode UTF-16 characters. Dart Runes are actually UTF-32 Unicode code points.They are UTF-32 string which is used to print special symbols.For example, the theta symbol in dart is displayed when we assign the Unicode equivalent value of '\u0398' to a variable.ExampleConsider the example shown below − Live Demovoid main(){    var heartSymbol = '\u0398';    print(heartSymbol); }OutputΘThere are different methods/properties that we can apply on dart Runes to extract the string core units. These mainly are −string.codeUnitAt()string.codeUnitsstring.runesstring.codeUnitAt()The string.codeUnitAt() method is used to access the character's code unit that is present inside ... Read More

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 More

Relational operators are used in cases where we want to compare two operands. The result when we use a relational operator between two operands is always a Boolean value.There are different types of relational operators present in Dart. In the table shown below all the relational operators present in dart are mentioned.Let's take a case where we have two variables x and y, with values 20 and 30 respectively.Consider the table shown below as a reference −OperatorDescriptionOutput>Greater thanx > y = false=Greater than or equal tox >= y = false

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 − Live Demoimport 'dart:io'; void main(List arguments) {    stdout.write('What is your name?\r'); }OutputWhat is your ... Read More

A queue is a collection of objects. In Dart, we can do operations on both ends of the queue.A queue can be created by making use of the Queue class this present inside the collection library of dart.ExampleConsider the example shown below − Live Demoimport 'dart:collection'; void main() {    var queue = new Queue();    print(queue); }In the above example, we imported the collection library so that Queue class can be used from it and then we create a Queue and store it in a variable named queue, and finally we print whatever is inside the queue variable.Output{}We can add ... Read More

Optional parameters are those parameters that don't need to be specified when calling the function. Optional parameters allow us to pass default values to parameters that we define. There are two types of optional parameters, mainly −Ordered (positional) optional parametersNamed optional parametersOrdered Optional ParametersOrdered optional parameters are those parameters that are wrapped in [ ]. For example, void printSomething(int a, int b, [ int c = 10] ){    // function body }They give us the freedom to call the function with or without the third parameter.ExampleConsider the example shown below − Live Demovoid printSomething(int a, int b, [ int c ... Read More

Dart has different null aware operators that we can use to make sure that we are not accessing the null values and to deal with them in a subtle way.Mainly, these are −?? operator??= operator? operatorWe will go through each of them in the following article.?? operatorThe ?? operator returns the first expression if and only if it is not null.ExampleConsider the example shown below −void main() {    var age;    age = age ?? 23;    print(age);    var name = "mukul";    name = name ?? "suruchi";    print(name); }In the above example, we declared two ... Read More

Multilevel inheritance in dart is the case when different classes are inheriting in a form of chain, i.e., one class extends some parent class, and the other class extends the class that was extending the parent class.The syntactical representation of multilevel inheritance looks something like this −class A {} class B extends A {} class C extends B {}If we notice the above syntax, we can clearly see that the class A is the parent class for the class B, which is extending it. Also, the class B acts as a parent for class C, which is extending class B.Multilevel ... Read More

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 More

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 More