Is this the best way to separate code in iOS development?

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>IDECodeSnippetCompletionPrefix</key>
	<string>snippetAlert</string>
	<key>IDECodeSnippetCompletionScopes</key>
	<array>
		<string>All</string>
	</array>
	<key>IDECodeSnippetContents</key>
	<string>let alertController = UIAlertController(title: &lt;#T##String?#&gt;, message: &lt;#T##String?#&gt;, preferredStyle: &lt;#T##UIAlertController.Style#&gt;)
let firstAction = UIAlertAction(title: &lt;#T##String?#&gt;, style: .default, handler: &lt;#T##((UIAlertAction) -&gt; Void)?##((UIAlertAction) -&gt; Void)?##(UIAlertAction) -&gt; Void#&gt;)
let cancelAction = UIAlertAction(title: &lt;#T##String?#&gt;, style: .cancel, handler: nil)

alertController.addAction(firstAction)
alertController.addAction(cancelAction)
present(alertController, animated: true)</string>
	<key>IDECodeSnippetIdentifier</key>
	<string>8C458AD7-C631-457B-85CC-D2501E425D59</string>
	<key>IDECodeSnippetLanguage</key>
	<string>Xcode.SourceCodeLanguage.Swift</string>
	<key>IDECodeSnippetSummary</key>
	<string></string>
	<key>IDECodeSnippetTitle</key>
	<string>UIAlertController</string>
	<key>IDECodeSnippetUserSnippet</key>
	<true/>
	<key>IDECodeSnippetVersion</key>
	<integer>2</integer>
</dict>
</plist>

@IBAction func doSomething()
@IBAction func doSomething(sender: UIButton)
@IBAction func doSomething(sender: UIButton, forEvent event: UIEvent)

[[NSProcessInfo processInfo] operatingSystemVersion]

import 'package:flutter/material.dart';

void main() {
  runApp(
    new MaterialApp(
      title: 'Hello World App',
      home: new myApp(),
    )
  );
}

class myApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('Hello World App'),
      ),
      body: new Center(
        child: new Text(
          'Hello, world!'
        ),
      ),
    );
  }
}

<?php 
// PHP program to find nth 
// magic number 

// Function to find nth 
// magic number 
function nthMagicNo($n) 
{ 
	$pow = 1; 
	$answer = 0; 

	// Go through every bit of n 
	while ($n) 
	{ 
	$pow = $pow * 5; 

	// If last bit of n is set 
	if ($n & 1) 
		$answer += $pow; 

	// proceed to next bit 
	$n >>= 1; // or $n = $n/2 
	} 
	return $answer; 
} 

// Driver Code 
$n = 5; 
echo "nth magic number is ", 
	nthMagicNo($n), "\n"; 

// This code is contributed by Ajit. 
?> 

override func viewDidLoad() {
    super.viewDidLoad()
    // Swift block syntax (iOS 10+)
    let timer = Timer(timeInterval: 0.4, repeats: true) { _ in print("Done!") }
    // Swift >=3 selector syntax
    let timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: #selector(self.update), userInfo: nil, repeats: true)
    // Swift 2.2 selector syntax
    let timer = NSTimer.scheduledTimerWithTimeInterval(0.4, target: self, selector: #selector(MyClass.update), userInfo: nil, repeats: true)
    // Swift <2.2 selector syntax
    let timer = NSTimer.scheduledTimerWithTimeInterval(0.4, target: self, selector: "update", userInfo: nil, repeats: true)
}

// must be internal or public. 
@objc func update() {
    // Something cool
}

// MARK: - Properties

// MARK: - IBOutlets

// MARK: - Life cycle

// MARK: - Set up

// MARK: - IBActions

// MARK: - Navigation

// MARK: - Network Manager calls

// MARK: - Extensions

#include <iostream>
#include "unordered_set"
#include "basicActions.h"
using namespace std;

void createLoop(Node *head)
{
    Node *p = head;

    while (p->next != nullptr)
    {
        p = p->next;
    }
    p->next = head;
    return;
}

bool detectLoop(Node *head)
{
    unordered_set<Node *> s;
    Node *p = head;

    while (p != nullptr)
    {
        if (s.find(p) != s.end())
            return true;

        s.insert(p);
        p = p->next;
    }
    return false;
}

int main()
{
    Node *head = nullptr;
    insertAtEnd(head, 1);
    insertAtEnd(head, 2);
    insertAtEnd(head, 3);
    insertAtEnd(head, 4);
    insertAtEnd(head, 5);

    createLoop(head);

    detectLoop(head) ? cout << "Loop Detected.." << '\n' : cout << "No Loop Detected.." << '\n';
}

#include <iostream>
using namespace std;

struct hashing
{
    int value;
    int key;
};


void put(int value, hashing hash[],int n) {
    hash[value % n].value = value;
    hash[value % n].key = (value % n);
}

int get(int key, hashing hash[]) {
    return hash[key].value;
}

int main()
{
    int n;
    
    struct hashing hash[n];
    cin >> n;
    for (int t=0;t<n;t++) {
        put(t+1,hash,n);
        cout << "Inserted : " << (t+1) << endl;
    }
    int temp;
    cin >> temp;
    cout << get(temp,hash) << endl;
}

/*
 * script to export data in all sheets in the current spreadsheet as individual csv files
 * files will be named according to the name of the sheet
 * author: Michael Derazon
*/

function onOpen() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var csvMenuEntries = [{name: "export as csv files", functionName: "saveAsCSV"}];
  ss.addMenu("csv", csvMenuEntries);
};

function saveAsCSV() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheets = ss.getSheets();
  // create a folder from the name of the spreadsheet
  var folder = DriveApp.createFolder(ss.getName().toLowerCase().replace(/ /g,'_') + '_csv_' + new Date().getTime());
  for (var i = 0 ; i < sheets.length ; i++) {
    var sheet = sheets[i];
    // append ".csv" extension to the sheet name
    fileName = sheet.getName() + ".csv";
    // convert all available sheet data to csv format
    var csvFile = convertRangeToCsvFile_(fileName, sheet);
    // create a file in the Docs List with the given name and the csv data
    folder.createFile(fileName, csvFile);
  }
  Browser.msgBox('Files are waiting in a folder named ' + folder.getName());
}

function convertRangeToCsvFile_(csvFileName, sheet) {
  // get available data range in the spreadsheet
  var activeRange = sheet.getDataRange();
  try {
    var data = activeRange.getValues();
    var csvFile = undefined;

    // loop through the data in the range and build a string with the csv data
    if (data.length > 1) {
      var csv = "";
      for (var row = 0; row < data.length; row++) {
        for (var col = 0; col < data[row].length; col++) {
          if (data[row][col].toString().indexOf(",") != -1) {
            data[row][col] = "\"" + data[row][col] + "\"";
          }
        }

        // join each row's columns
        // add a carriage return to end of each row, except for the last one
        if (row < data.length-1) {
          csv += data[row].join(",") + "\r\n";
        }
        else {
          csv += data[row];
        }
      }
      csvFile = csv;
    }
    return csvFile;
  }
  catch(err) {
    Logger.log(err);
    Browser.msgBox(err);
  }
}

  var newStafflist = [];
  for (var i = 0; i < staffdata.length; i++) {
    var department = staffdata[i][4];
    if (depData.flat().includes(department) && department !== "") {
      newStafflist.push([staffdata[i][2], staffdata[i][3], staffdata[i][4], staffdata[i][5], staffdata[i][8], staffdata[i][9], staffdata[i][10], staffdata[i][7]]);
    }
  }

// Preferred status bar style lightContent to use on dark background.
// Swift 3
override var preferredStatusBarStyle: UIStatusBarStyle {
    return .lightContent
}

import UIKit

extension UITableView {
    
    func dequeueReusableCell<T: UITableViewCell>() -> T {
        return dequeueReusableCell(withIdentifier: NSStringFromClass(T.self)) as! T
    }
}

//using: let cell: ExampleTableViewCell = tableView.dequeueReusableCell()

let url = URL(string: image.url)
let data = try? Data(contentsOf: url!) //make sure your image in this url does exist, otherwise unwrap in a if let check / try-catch
imageView.image = UIImage(data: data!)

function aaa(a, b){
return a+b;
}