Fresh Flutter project has error: The function ‘runApp’ isn’t defined

I’m trying to test flutter with flutter create app_name and using Android Studio and VS Code I get the error on runApp isn’t defined, and indeed no where in the flutter library I can see this is being defined.

Strangely, first time I created a template app it had a different template and more lines at import library but after second attempt the import line is only one limited to: import 'package:flutter/material.dart'; which of course does not include runApp()

import 'package:flutter/material.dart';


void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

Solution:

re-install flutter in

C:\src\flutter