DART

flutter main.dart

import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
 const MyApp({Key? key}) : super(key: key);
@override
  Widget build(BuildContext context) {
    return const MaterialApp(
           home: Text("Hello World Niluka"),
         );
    }
}

Main function for flutter

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

dart main function

void main()
{
    //main() function body 
}

dart main

void main(List<String> arguments /* optional */) {
    // ...
}