loop.php  simple loop example
  php source code
    $a = 0;
    $b = 0;
    for($i=0; $i<5; $i++)
    {
      $a += 10;
      $b += 5;
    }
    echo ("At the end of the loop a = $a and b = $b 
\n" );

  At the end of the loop a = 50 and b = 25