Swift - Classes

Classes in Swift 4 are building blocks of flexible constructs. Similar to constants, variables and functions the user can define class properties and methods. Swift 4 provides us the functionapty that while declaring classes the users need not create interfaces or implementation files. Swift 4 allows us to create classes as a single file and the external interfaces will be created by default once the classes are initiapzed.

Benefits of having Classes

Inheritance acquires the properties of one class to another class

Type casting enables the user to check class type at run time

Deinitiapzers take care of releasing memory resources

Reference counting allows the class instance to have more than one reference

Common Characteristics of Classes and structures

Properties are defined to store values

Subscripts are defined for providing access to values

Methods are initiapzed to improve functionapty

Initial state are defined by initiapzers

Functionapty are expanded beyond default values

Confirming protocol functionapty standards

Syntax

Class classname {
   Definition 1
   Definition 2
   --- 
   Definition N
}

Class Definition

class student {
   var studname: String
   var mark: Int 
   var mark2: Int 
}

The syntax for creating instances

let studrecord = student()

Example

class MarksStruct {
   var mark: Int
   init(mark: Int) {
      self.mark = mark
   }
}

class studentMarks {
   var mark = 300
}

let marks = studentMarks()
print("Mark is (marks.mark)")

Mark is 300

class MarksStruct {
   var mark: Int
   init(mark: Int) {
      self.mark = mark
   }
}

class studentMarks {
   var mark1 = 300
   var mark2 = 400
   var mark3 = 900
}

let marks = studentMarks()
print("Mark1 is (marks.mark1)")
print("Mark2 is (marks.mark2)")
print("Mark3 is (marks.mark3)")

Mark1 is 300
Mark2 is 400
Mark3 is 900

class SampleClass: Equatable {
   let myProperty: String
   init(s: String) {
      myProperty = s
   }
}

func ==(lhs: SampleClass, rhs: SampleClass) -> Bool {
   return lhs.myProperty == rhs.myProperty
}

let spClass1 = SampleClass(s: "Hello")
let spClass2 = SampleClass(s: "Hello")

spClass1 === spClass2 // false
print("(spClass1)")

spClass1 !== spClass2 // true
print("(spClass2)")

main.SampleClass
main.SampleClass