class vs struct

Class

• class is reference type.
• class object is created on Heap memory.
• For class member variable can initialised directly.
• class have constructor and destructor methods of all types.
• class can inherit another class.
• class are good for larger or complex object.

Struct

• struct is value type.
• struct object is created on Stack memory.
• For struct member vaiable can not initialised directly.
• struct can't be abstract.
• stucts are good for small and isolated model object.  

Example of class

- created one Student class with name and lname property with init method

class Student{

    var name : String?

    var lname : String?

    init(name : String?,lname : String?) {

        self.name = name

        self.lname = lname

    }

}

- now create one object for Student class called objStudent and print

let objStudent = Student(name: "Pratik", lname: "Lad")

dump(objStudent)

Output :

__lldb_expr_44.Student #0

  ▿ name: Optional("Pratik")

    - some: "Pratik"

  ▿ lname: Optional("Lad")

    - some: "Lad"

- now one more object create and assign older object of Student class

let obj1Student = objStudent

- now change the name of obj1Student object

obj1Student.name = "Bunty"

- now print both object 

dump(objStudent)

Output :

__lldb_expr_44.Student #0

  ▿ name: Optional("Bunty")

    - some: "Bunty"

  ▿ lname: Optional("Lad")

    - some: "Lad"

dump(obj1Student)

Output :

__lldb_expr_44.Student #0

  ▿ name: Optional("Bunty")

    - some: "Bunty"

  ▿ lname: Optional("Lad")

    - some: "Lad"

you can see the objStudent object name also change because class is reference type.

Example of struct

- created one Student struct with name and lname property with init method

struct Student{

    var name : String?

    var lname : String?

    init(name : String?,lname : String?) {

        self.name = name

        self.lname = lname

    }

}

- now create one object for Student struct called objStudent and print

let objStudent = Student(name: "Pratik", lname: "Lad")

dump(objStudent)

Output :

__lldb_expr_44.Student #0

  ▿ name: Optional("Pratik")

    - some: "Pratik"

  ▿ lname: Optional("Lad")

    - some: "Lad"

- now one more object create and assign older object of Student struct

var obj1Student = objStudent

- now change the name of obj1Student object

obj1Student.name = "Bunty"

- now print both object 

dump(objStudent)

Output :

__lldb_expr_44.Student #0

  ▿ name: Optional("Pratik")

    - some: "Bunty"

  ▿ lname: Optional("Lad")

    - some: "Lad"

dump(obj1Student)

Output :

__lldb_expr_44.Student #0

  ▿ name: Optional("Bunty")

    - some: "Bunty"

  ▿ lname: Optional("Lad")

    - some: "Lad"

you can see the objStudent and obj1Student object name not change because struct is value type.

Thanks for reading this article.

Tuples

Why Tuples ?
Swift 4 has introduced tuples to help us to return multiple values from a function instead of only one value.
Tuples is multiple values grouped into a single compound value. The values can be of any type, it need not necessarily to be of same type.
Tuples type is comma-seperated list types, enclosed in parentheses.
Tuples are created by grouping any amount of values.

Please check below examples for different uses of tuples :

---------------------------------------------------------------------------------

Displaying tuple value using variable name

1) Same Data type

let multipleValue : (value1 : String,value2 : String) = ("iOS","Android")

print(multipleValue.value1)

print(multipleValue.value2)

Output

iOS

Android

---------------------------------------------------------------------------------

Different Data type

1) Displaying tuple value using index (without variable name)

let multipleValue = ("iOS", "Android", 5)

print(multipleValue.0) 

print(multipleValue.1)

print(multipleValue.2)

Output :

iOS

Android

5

2) Displaying tuple value using variable names

let multipleValue = (name: "iOS",name1: "Android",value1: 5)

print(multipleValue.name)

print(multipleValue.name1)

print(multipleValue.value1)

Output :

iOS

Android

5

---------------------------------------------------------------------------------

Displaying tuples as optionals

var multipleValue : (name: String,name1: String?,value1: Int)

multipleValue = ("iOS",nil,5)

print(multipleValue.name)

print(multipleValue.name1)

print(multipleValue.value1)

Output

iOS

nil

5

---------------------------------------------------------------------------------

Tuples usage in function return type

1) Displaying tuple value using index (without variable name)

func test() -> (String,Int) {

    return ("iOS",11)

}

print(test().0)

print(test().1)

Output

iOS

11

2) Displaying tuple value with variable name

func test() -> (name : String,version : Int) {

    return ("iOS",11)

}

print(test().name)

print(test().version)

Output

iOS

11

---------------------------------------------------------------------------------

For more info, click on below link :-

https://www.youtube.com/watch?v=MwOv844k9-4&t=222s

Thank you.

Enum

Enum is data type for consisting name value like String, Int etc.
For good programer practice code is readable and reusable.
Enum is best for comparing in conditional statement and switch case.

For example if we match string type value like

func getDevice(forDeviceType deviceType : String){

    if deviceType == "iOS"{

        print("iOS")

    }else{

        print("Other device")

    }

}

Now how to use enum string type for above function 

enum enumDeviceType : String {

    case iOS

    case Android

}

func getDevice(forDeviceType deviceType : String){

    if deviceType == enumDeviceType.iOS.rawValue{

        print("iOS device")

    }else{

        print("Other device")

    }

}

another example of enums

enum myEnumList{

    case list1

    case list2

    

    var noOfItems : Int{

        switch self {

        case .list1:

            return 50

        case .list2:

            return 100

        }

    }

}

func listEnumTest(type : myEnumList)

{

    switch type {

    case .list1:

        print("hello list 1 total item is \(type.noOfItems)")

        break

    case .list2:

        print("hello list 2 total item is \(type.noOfItems)")

        break

    }

}

listEnumTest(type: .list1)

you can also watch video 

If you have any trouble in use of enum then pls comment 

Thank you

Generics in iOS Swift

The main use of Generic is avoid code duplication.
Generic placeholder is defined within angle brackets <>.

For example there are two array with different type.

let arrayOfInt = [5,10,15,20]

let arrayOfString = ["Karan","Ankur","Bunty"]

For print this array of value you can create two function like

func printInt(fromArrayOfInt arrayOfInt:[Int]){

    arrayOfInt.map({print($0)})

}

func printString(fromArrayOfString arrayOfString:[String]){

    arrayOfString.map({print($0)})

}

And use

printInt(fromArrayOfInt: arrayOfInt)

printString(fromArrayOfString: arrayOfString)

Output:

5

10

15

20

Karan

Ankur

Bunty

Now using Generic no need to create two function. We can print all type of array using single function like 

func printArray<T>(fromArray arrayOfValue: [T]){

    arrayOfValue.map({print($0)})

}

and calling is same

printArray(fromArray: arrayOfInt)

printArray(fromArray: arrayOfString)

In order to use Generic with struct, class or enum, you can define the Generic placeholder after the name. 

Github link : Generics

You can also watch video :