Swift: the beginning

NO Semicolons

Variables (and strings)      var variable_name:Type = initial_value

var name_variable:String

var name:String= "Hello"      // intialize to a string

var name = "Hello"        //notice I did not type it as a String---swift figures it out by initialization value

Constants

let constant_name:Type = initial_value

Examples

›let name:String= "Hello"    // intialize to a string

›let name = "Hello"   //notice I did not type it as a                 //String---swift figures it out by initialization value

 

Data Types

• String

• Int

• Float

Print

println(“Hello   /(var_name)” )

Above will print out:

 Hello  value_variable

 

Functions

No return, no parameters:

›Example funtion with no return or parameters

func sayHello() {

     println(“hello”)

}

›To invoke this function

sayHello()

 

Have parameters, explicitly give a name exposure (DIFFERENT)

›Example function with parameters

NOTE:
nameofPerson declaration is used when expose definition of this function

func sayHelloToName(nameOfPerson name: String) {

     println(“hello \(name)”)

}

›To invoke this function

sayHelloToName(nameOfPerson: “Lynne”)

 

Have parameters, NO explicitlyname exposure (LIKE MOST LANGUAGES)

›Example function with parameters

func sayHelloToName(name: String) {

     println(“hello \(name)”)

}

›To invoke this function

sayHelloToName(: “Lynne”)

 

Return a value

Example, return a string (see declaration -> String)

func sayHelloToName(name: String) -> String {

     println(“hello \(name)”)

     return “Hello to you to!”

}

›To invoke this function

var message:String = sayHelloToName(“Lynne”)

 

Return Multiple Values

 

›Example function with return of a tuple – 2 values

func sumCeil(a:Int, b:Int) -> [Int, Int] {

     var ceil =a > b ? a : b

     var sum = a+b

     return (sum, ceiling)

}

›To invoke this function

var total:Int = sumCeil(2, 33)

println( “values are sum= /(total.sum)   and  ceiling = /(total.ceil)”)

// NOTE: total.0 = sum value    AND total.1 = ceiling

 

 

Return Multiple Values --and explicitly name them

 

›Example function with return of a tuple – 2 values

func sumCeil(a:Int, b:Int) -> [sum:Int, ceil:Int] {

     var ceil =a > b ? a : b

     var sum = a+b

     return (sum, ceiling)

}

›To invoke this function

var total:Int = sumCeil(2, 33)

// NOTE: total.sum = sum value    AND total.ceil = ceiling

 

Creating Instance of Class

 

›Call Constructor

Example, using UIView that is part of iOS UIKit package

import UIKit

var view = UIView()

view.backgroundColor = UIColor.yellowColor()

Classes