Basic Concepts of Scala (Class -23)

 Before writing Scala Programming Language, we need to know basic Scala concepts:

Basic Scala Concepts	Meaning	Example
Class	a blueprint that defines the states and behaviors related to it.	Fields, variables, function objects, methods
Object	an instance of a Class. it has states and behavior.  It is created using the new keyword.	var obj = new Class();
Methods	a block of code that can perform a certain amount of tasks.	def methodName (parameters) : (return Type)
Fields	variables defined inside the Class body. states of Objects.	Mutable fields (var) and Immutable fields (val).
Closure	a function whose value depends on the value of multiple variables that are declared outside the function.	val multiplier = (i:Int) => i * 10
Traits	just like classes they have fields and methods but multiple traits can be used together(inherited) to increase the functionality of a class.	trait trait_name {      def method()     }
Wrapper Class	used to put primitive data value into an object.	Byte, Short, Integer, Long, Float, Double, Character, Boolean
Identifiers	are the names given to a class, method, variable or object to identify them in the program.	myObject, main, args, value1. etc. (not keywords / digits)
Code block	multiple lines of code that have only one entry and one exit point.	{ } used in methods, class definition, loop statements and logic.
Variables	reference to a memory location where data is stored.	val, var & lazy.
Data Types	tells the compiler about the type of data that is used by the programmer.	Boolean, Integer, Float, Double, Char, String, Nothing, Any, anyRef, anyVar, etc.
any' class	Superclass of all classes in Scala.  Root of the class hierarchy.	Two subclasses they are: 1) anyRef, 2) anyVar
Nothing	subtype of all types in Scala.	Nothing is a subtype of Char, Float, Int.
Lazy variable	saves memory when variables declared are not used while object creation.	lazy val
Type interface	used to make the declaration of data type optional.	compilers work to detect the data type.
Operators	tell the compiler to perform a specific operation.	Plus (+), And (&), Or (I), etc.
Numeric type	deals with all types that are stored in Integers and Decimals.	Float, Double, Int, Short, Long
Unit type	used as a return statement for a function when no value is to be returned.	compared to void data type and is a subclass of anytype trait.
Option	container that contains one single value which can be one of the two distinct values.	One of the two values is 'none' and others can be any object valid in the program.
Basic program	three parts - the Class definition, Main() function and the Print statement.	object MyClass {         def main(args: Array[String]) {          print("Hello World!"); } }
Method parameters	hose variables which are passed to the method while calling the method.	add(a:Int , b:Int)
Literals	basic constants value that can be assigned to a variable.	var i = 10L; var I = 123.54d
Expressions	A line of code that can be compiled and has some resultant value. These are displayed on screen using println statements.	println(45 * 24332);
Function	a reusable chunk of code that can perform the operation on the value passed as a parameter.	val result = (mark: Float )
Block	multiple statements that are enclosed between curly braces.	{ // statement 1     // statement 2  … }