斐波纳契数列通常做法是用递归实现，当然还有其它的方法。这里现学现卖，用PHP的迭代器来实现一个斐波纳契数列，几乎没有什么难度，只是把类里的next()方法重写了一次。注释已经写到代码中，也是相当好理解的。
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/** |
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* @author 简明现代魔法 http://www.nowamagic.net |
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*/ |
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class Fibonacci implements Iterator {
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private $previous = 1;
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private $current = 0;
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private $key = 0;
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public function current() {
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return $this->current;
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}
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public function key() {
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return $this->key;
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}
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public function next() {
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// 关键在这里
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// 将当前值保存到 $newprevious
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$newprevious = $this->current;
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// 将上一个值与当前值的和赋给当前值
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$this->current += $this->previous;
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// 前一个当前值赋给上一个值
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$this->previous = $newprevious;
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$this->key++;
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}
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public function rewind() {
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$this->previous = 1;
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$this->current = 0;
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$this->key = 0;
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}
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public function valid() {
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return true;
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}
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} |
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$seq = new Fibonacci;
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$i = 0;
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foreach ($seq as $f) {
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echo "$f ";
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if ($i++ === 15) break;
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} |
程序运行结果：
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0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 |