用PHP迭代器回实现一个斐波纳契数列

<?php /*[email&#160;protected] [email&#160;protected]*/class Fibonacci implements Iterator {     private $previous = 1;     private $current = 0;     private $key = 0;         public function current() {         return $this->current;     }         public function key() {         return $this->key;     }         public function next() { 		// 关键在这里		// 将当前值保存到  $newprevious        $newprevious = $this->current; 		// 将上一个值与当前值的和赋给当前值        $this->current += $this->previous; 		// 前一个当前值赋给上一个值        $this->previous = $newprevious;         $this->key++;     }         public function rewind() {         $this->previous = 1;         $this->current = 0;         $this->key = 0;     }         public function valid() {         return true;     } } $seq = new Fibonacci; $i = 0; foreach ($seq as $f) {     echo "$f ";     if ($i++ === 15) break; } ?>

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