保留应用程序执行期间生成的随机数，直到应用程序在Swift中退出

// AppDelegate.swift

import Foundation

var generatedRandomNumber: Int?

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    // ...
}

// RandomNumberManager.swift

import Foundation

class RandomNumberManager {
    static let shared = RandomNumberManager()
    
    var generatedRandomNumber: Int?
    
    private init() { }
    
    func generateRandomNumber() -> Int {
        let randomNum = Int.random(in: 1...100)
        generatedRandomNumber = randomNum
        return randomNum
    }
}

// ViewController.swift

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 生成随机数
        let randomNum = RandomNumberManager.shared.generateRandomNumber()
        print("Generated Random Number: \(randomNum)")
        
        // 访问已生成的随机数
        if let storedRandomNum = RandomNumberManager.shared.generatedRandomNumber {
            print("Stored Random Number: \(storedRandomNum)")
        }
    }
}