PHP 致命错误：未捕获错误：Class 未找到“Symfony\Component\Console\Application”

Question

I am trying to create a simple CLI app with PHP but I keep getting:

PHP Fatal error:  Uncaught Error: Class 'Symfony\Component\Console\Application' not found in /Applications/MAMP/htdocs/newcli/dan.php:6
Stack trace:
#0 {main}
  thrown in /Applications/MAMP/htdocs/newcli/dan.php on line 6

Fatal error: Uncaught Error: Class 'Symfony\Component\Console\Application' not found in /Applications/MAMP/htdocs/newcli/dan.php:6
Stack trace:
#0 {main}
  thrown in /Applications/MAMP/htdocs/newcli/dan.php on line 6

What am I doing wrong? My PHP version: PHP 7.1.0RC6 (cli) (built: Nov 9 2016 04:45:59) ( NTS )

dan.php:

#! usr/bin/env php
<?php use Symfony\Component\Console\Application;

require 'vendor/autoload.php';

$app = new Application('Task App', '1.0');

$app->add(new Acme\ShowCommand());
$app->run();

Answer 1

The use statement must be placed after the require 'vendor/autoload.php'

#! usr/bin/env php
<?php 

require 'vendor/autoload.php';

use Symfony\Component\Console\Application;

$app = new Application('Task App', '1.0');

$app->add(new Acme\ShowCommand());
$app->run();

Answer 2

Some classes can be absent in your vendor . So, it can be resolved by a composer install .