printf和sprintf的应用

<!--?php  
printf('b: %b <br-->c: %c <br>d: %d <bf>f: %f', 80,80, 80, 80);  
echo '<br>';  
printf('%0.2f <br>%+d <br>%0.2f <br>', 8, 8, 1235.456);  
  
printf('the cost of %d %s at $%0.2f each is $%0.2f.', 4, 'brooms', 8.50, (4*8.50));  
  
echo '<br>';  
$tax = 30;  
printf('The tax rate is %0.2f%%', $tax);</bf>

Sprint可以把查询和数据很好的分开代码

  
  
  
    <meta charset="utf-8">  
    <title>Sorting Multidimensional Arrays</title>  
  
  
<!--?php  
$db = mysqli_connect('192.168.31.172', 'root', 'root', 'phpadvanced');  
mysqli_query($db, "set names utf8");  
  
if(!empty($_POST['task'])) {  
    $parent_id = 0;  
    if(isset($_POST['parent_id']) && filter_var($_POST['parent_id'], FILTER_VALIDATE_INT, ['min_range' =--> 1])) {  
        $parent_id = $_POST['parent_id'];  
    }  
  
    $q = sprintf("INSERT INTO tasks (parent_id, task) VALUES (%d, '%s')", $parent_id, mysqli_real_escape_string($db, strip_tags($_POST['task'])));  
    $r = mysqli_query($db, $q);  
  
    if(mysqli_affected_rows($db) == 1) {  
        echo '<p>任务添加成功</p>';  
    } else {  
        echo '<p>任务添加失败</p>';  
    }  
}  
?>  
      
  
<!--?php  
    // 对任务的父id进行排序  
    function parent_sort($x, $y) {  
        return ($x['parent_id'] --> $y['parent_id']);  
    }  
    usort($tasks, 'parent_sort');  
    echo '<h2>当前的任务列表</h2><ul>';  
    foreach ($tasks as $task) {  
        echo "<li>{$task['task']}</li>\n";  
    }  
echo '</ul>';  
?>