Choose the correct answer?

import Foundation

import AVFoundation

func startCapture()

{ if let device : AVCaptureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeAudio){ do { self.session = AVCaptureSession() try device.lockForConfiguration() let audioInput = try AVCaptureDeviceInput(device: device) device.unlockForConfiguration() // audio capture operation … … } catch { } } }

How to convert string into integer value? import UIKit let str_number = '320'

Output when the file doesn’t exist? import UIKit let filename:String = 'testfile'; var readdata:String = 'test data';

Extensions can add new instance ____?

Output? import UIKit var str1:String?='text1'; var str2:String='text2'; var int1:Int?=111; var int2:Int=222; var array:String[] = [str1, str2, int1, int2]; array=[];

Use the classes defined above to create a new Person instance, and try to access its numberOfRooms property as before?

What is the super class name? class Square: NamedShape { var sideLength: Double func area() -> Double { return sideLength * sideLength } }

What is the correct way to compare the equality of two String type objects in Swift?

Which is not a control transfer statement in Swift?

Which keyword do you use to define a class?

What is a mutating instance method in Swift?