PHP单例模式

<?phpclass single{public $out;public function a($a){ ???$this->out .= $a; ???return $this;}public function b($b){ ???$this->out .= $b; ???return $this;}public function say(){ ???echo $this->out.PHP_EOL;}public function get(){ ???return $this->out;}}$single = new single();$out = $single->a(‘a‘)->b(‘b‘)->say();$get = $single->a(‘a‘)->b(‘b‘)->get();echo $get;

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