标签：style blog http io ar for sp div on
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。定州市科技工业局
01 |
/** |
02 |
* @author 简明现代魔法 http://www.nowamagic.net |
03 |
*/ |
04 |
class Fibonacci implements Iterator { |
05 |
private $previous = 1; |
06 |
private $current = 0; |
07 |
private $key = 0; |
08 |
09 |
public function current() { |
10 |
return $this->current; |
11 |
} |
12 |
13 |
public function key() { |
14 |
return $this->key; |
15 |
} |
16 |
17 |
public function next() { |
18 |
// 关键在这里 |
19 |
// 将当前值保存到 $newprevious |
20 |
$newprevious = $this->current; |
21 |
// 将上一个值与当前值的和赋给当前值 |
22 |
$this->current += $this->previous; |
23 |
// 前一个当前值赋给上一个值 |
24 |
$this->previous = $newprevious; |
25 |
$this->key++; |
26 |
} |
27 |
28 |
public function rewind() { |
29 |
$this->previous = 1; |
30 |
$this->current = 0; |
31 |
$this->key = 0; |
32 |
} |
33 |
34 |
public function valid() { |
35 |
return true; |
36 |
} |
37 |
} |
38 |
39 |
$seq = new Fibonacci; |
40 |
$i = 0; |
41 |
foreach ($seq as $f) { |
42 |
echo "$f "; |
43 |
if ($i++ === 15) break; |
44 |
} |
程序运行结果：
1 |
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 |
标签：style blog http io ar for sp div on
原文地址：http://www.cnblogs.com/xiaoyang002/p/4022138.html
