text: import React, { Component } from "react";
  import { BrowserRouter as Router, Switch, Link, Route } from "react-router-dom";
  import Add from "./Add";
  import Listing from "./Listing";
  import Edit from "./Edit";
  
  export default class Index extends Component {
      render() {
          return (
              <Router>
                  <div>
                      <nav className="navbar navbar-default">
                          <div className="container-fluid">
                              <div className="navbar-header"></div>
                              <ul className="nav navbar-nav">
                                  <li>
                                      <Link to="/listing">Listing</Link>
                                  </li>
                                  <li>
                                      <Link to="/add">Add</Link>
                                  </li>
                              </ul>
                          </div>
                      </nav>
  
                      <Switch>
                          <Route exact path="/listing">
                              <Listing />
                          </Route>
                          <Route exact path="/add">
                              <Add />
                          </Route>
                          <Route exact path="/category/edit/:id" component={Edit} />
                         
                      </Switch>
                  </div>
              </Router>
          );
      }
  }
  