const express = require('express');

const app =  express();

app.get('/', function (req, res) {

    res.send('root');

});

app.get('/about', function (req, res) {

    res.send('about');

});

app.get('/random.txt',function (req, res) {

    res.send('random.txt');

});

//  abc  abd

app.get('/ab?cd',function (req, res) {

    res.send('ab?cd');

});

// abbcd abbbcd and so on

app.get('/ab+cd', function (req, res) {

    res.send('ab+cd');

});

// adRANDOMcd

app.get('/ab*cd', function (req, res) {

    res.send('ab*cd');

});

//. ade adcde

app.get('/ab(cd)?e', function (req, res) {

    res.send("ab(cd)?e");

});

app.listen(,function () {

    console.log("learning express router");

});