Swift Basics - Playground(Xcode), Data type, Function

Basic Flow of Application

reference : https://www.youtube.com/watch?v=F2ojC6TNwws

Xcode - Playground 

It provides a simple tool called "playground" which enables to practice Swift. It also has advantages on as following; 

• REPL - Read, Eval, Print, Loop 가능
• 프로젝트 생성 불필요 
• 코드 작성/변경 - 바로 결과 확인 가능 

Swift

Data-type 

• String : "Hello"
• Int : 1,2, 
• Double : 0.2, 1.2
• Bool : ture, false 
• var : mutable variable 
• let : immutable variable 
• uses Camel case 
•  

Function

- Basic call 

 

1. func functionName () {}

 --> type 'func' in front of the name of the function 

 

2. Parameters 

--> Swift has various ways to assign parameters of a function, and depending on the way it is stated, it is considered as a different function even if the name of the function is duplicated with the others.

Example) 

func myFunc(){

	let a = 10 
	let b = 10 
    print(a+b)

}

func myFunc(a:Int , b:Int){

    print(a-b)

}


func myFunc(firstNum a:Int, secondNum b:Int){

    print(a*b)

}

myFunc()
myFunc(a: 10, b: 20)
myFunc(firstNum: 5, secondNum: 4)

3. return 

Declare the type of return followed by '->' after parameter declaration.

func myFunc(firstNum a:Int, secondNum b:Int) -> Int{

    return a*b

}