title: react app looks different from one in w3school and other tutorials
body: <p>this is the default app code in w3school or other courses in their directory (/myfirstreact/src/App.js:) :</p>
  
  <pre><code>import React, { Component } from 'react';
  import logo from './logo.svg';
  import './App.css';
  
  
  
  class App extends Component{
        render() {
          return (
            &lt;div className="App"&gt;
              &lt;header className="App-header"&gt;
                &lt;img src={logo} className="App-logo" alt="logo" /&gt;
                &lt;p&gt;
                  Edit &lt;code&gt;src/App.js&lt;/code&gt; and save to reload.
                &lt;/p&gt;
                &lt;a
                  className="App-link"
                  href="https://reactjs.org"
                  target="_blank"
                  rel="noopener noreferrer"
                &gt;
                  Learn React
                &lt;/a&gt;
              &lt;/header&gt;
            &lt;/div&gt;
          );
        }
      }
  
      export default App;
  </code></pre>
  
  <p>and this is mine :  </p>
  
  <pre><code>import React from 'react';
  import logo from './logo.svg';
  import './App.css';
  
  function App() {
    return (
      &lt;div className="App"&gt;
        &lt;header className="App-header"&gt;
          &lt;img src={logo} className="App-logo" alt="logo" /&gt;
          &lt;p&gt;
            Edit &lt;code&gt;src/App.js&lt;/code&gt; and save to reload.
          &lt;/p&gt;
          &lt;a
            className="App-link"
            href="https://reactjs.org"
            target="_blank"
            rel="noopener noreferrer"
          &gt;
            Learn React
          &lt;/a&gt;
        &lt;/header&gt;
      &lt;/div&gt;
    );
  }
  
  export default App;
  </code></pre>
  
  <p>i still didn't change anything and i cant follow the course with this different code 
  and even when i manually type the default code i get lots of errors !!!!
  can someone please tell me how can i solve this ??</p>