Debugging iOS Applications

print("Current user ID: 12345")
print("App state: running")

let userName = "Alice"
let userAge = 30
print("User \(userName) is \(userAge) years old")

func calculateAverage(_ numbers: [Int]) -> Double {
    var sum = 0
    for number in numbers {
        sum += number // Set conditional breakpoint here with condition: number > 10
    }
    return Double(sum) / Double(numbers.count)
}

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        let message = "Hello, World!"
        print(message)
    }
}

// In Xcode, select Debug > View Debugging > Capture View Hierarchy
// This captures the current UI state for inspection

class ViewController: UIViewController {
    var largeArray = [String](repeating: "Memory", count: 100000)
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Memory graph will show largeArray allocation here
    }
}

# Open Instruments from Xcode
open -a "Instruments"

# Or use the command line
xcrun instruments -t "Blank Template" -w "<device>"

class ViewController: UIViewController {
    var timer: Timer?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // This creates a retain cycle
        timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { [weak self] _ in
            print("Timer fired")
        }
    }
}

sudo /System/Library/Frameworks/NetworkLinkConditioner.framework/Versions/Current/Resources/NetworkLinkConditioner --enable

sudo /System/Library/Frameworks/NetworkLinkConditioner.framework/Versions/Current/Resources/NetworkLinkConditioner --disable

override func viewDidLoad() {
    super.viewDidLoad()
    
    // Enable constraint debugging
    view.addSubview(myView)
    myView.translatesAutoresizingMaskIntoConstraints = false
    
    NSLayoutConstraint.activate([
        myView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
        myView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
        myView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
        myView.heightAnchor.constraint(equalToConstant: 100)
    ])
    
    // Enable visual debugging in Xcode
    myView.debugDescription // This will show constraint details in console
}

import os.log

let logger = OSLog(subsystem: "com.example.app", category: "UI")

os_log("User tapped button", log: logger, type: .debug)
os_log("Loading data from API", log: logger, type: .info)
os_log("Failed to load data", log: logger, type: .error)

import os.log

let customLogger = OSLog(subsystem: "com.example.app", category: "Network")

// Define custom log levels
let networkLog = OSLog(subsystem: "com.example.app", category: "Network")

os_log("Request to https://api.example.com", log: networkLog, type: .info)
os_log("Response received with status 200", log: networkLog, type: .debug)

struct Person {
    let name: String
    let age: Int
}

extension Person: CustomDebugStringConvertible {
    var debugDescription: String {
        return "Person(name: "\(name)", age: \(age))"
    }
}

let person = Person(name: "Alice", age: 30)
print(person.debugDescription)
// Output: Person(name: "Alice", age: 30)