printf和sprintf的应用

c: %c 
d: %d f: %f', 80,80, 80, 80);  
echo '
';  
printf('%0.2f 
%+d 
%0.2f 
', 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 '
';  
$tax = 30;  
printf('The tax rate is %0.2f%%', $tax);

Sprint可以把查询和数据很好的分开代码

  
  
  
      
      
  
  
 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 '
任务添加成功
';  
    } else {  
        echo '
任务添加失败
';  
    }  
}  
?>  
      
  
 $y['parent_id']);  
    }  
    usort($tasks, 'parent_sort');  
    echo '
当前的任务列表
';  
    foreach ($tasks as $task) {  
        echo "
{$task['task']}
\n";  
    }  
echo '
';  
?>