php 斐波那契数列

 function fib($n)
  {
      $cur = 1;
      $prev = 0;
      for ($i = 0; $i < $n; $i++) {
          yield $cur;

          $temp = $cur;
          $cur = $prev + $cur;
          $prev = $temp;
      }
  }

  $fibs = fib(9);
  foreach ($fibs as $fib) {
      echo " " . $fib;
  }

  // output:    1 1 2 3 5 8 13 21 34