What is entry point of iOS Application?

Ans : 

In mostly language, There is having main method in main file which is starting point of project. In iOS, also same approach are there.

Objective-C :

main.m File :

int main(int argc, char * argv[]) {

        NSString * appDelegateClassName;

        @autoreleasepool {

            // Setup code that might create autoreleased objects goes here.

            appDelegateClassName = NSStringFromClass([AppDelegate class]);

        }

        return UIApplicationMain(argc, argv, nil, appDelegateClassName);

        

        

    }

Swift : 

AppDelegate.swift

import UIKit

import CoreData

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate {

In Swift, @UIApplicationMain attribute is a replacement of main.m file & and entry point for your application to start.