1. Which of the following will not add john to the users array?
1. $users[] = ‘john’;
2. array_add($users,’john’);
3. array_push($users,’john’);
4. $users ||= ‘john’;
Answer: 2,4
2. What’s the difference between sort(), asort() and ksort(),rsort()? Under what circumstances would you use each of these?
sort(): 本函数对数组的值进行排序。当本函数结束时数组单元将被从最低到最高重新安排,array 中的单元赋予新的键名。这将删除原有的键名而不仅是重新排序。
asort(): 这个函数将数组的值重新排序，由小至大排列。数组的索引亦跟着值的 顺序而变动。当您在程序中需要重新整理数组值的 顺序时，就可以使用这个函数。
ksort(): 对数组按照键名排序，保留键名到数据的关联。本函数主要用于关联数组。
rsort(): 本函数对数组进行逆向排序(最高到最低)。与sort()执行相反的.操作。
3. What would the following code print to the browser? Why?
$num = 10;
function multiply(){
$num = $num * 10;
}
multiply();
echo $num;
10
4. What is the difference between a reference and a regular variable? How do you pass by reference & why would you want to?
pass by reference like this functions(&$vars);
it likes more fast;
5. What functions can you use to add library code to the currently running script?
inlcude() or require();
6. What is the difference between foo() & @foo()?
if foo() throw a error, will be alert, but @foo() no;
7. How do you debug a PHP application?
xdebug or use die() do it;
8. What does === do? What’s an example of something that will give true for ‘==’, but not ‘===’?
=== 用于精确比较 ex: (” == null) => true but ( ”===null) =>false;
9. How would you declare a class named “myclass” with no methods or properties?
class myclass{
}
10. How would you create an object, which is an instance of “myclass”?
$myoject = new myclass();
11. How do you access and set properties of a class from within the class?
getVar() or setVar() ;
12. What is the difference between include & include_once? include & require?
require:PHP 程式在执行前，就会先读入 require 所指定引入的档案，使它变成 PHP 程式网页的一部份。常用的函式，亦可以这个方法将它引入网页中。错误产生致命错误。
include:这个函式一般是放在流程控制的处理区段中。PHP 程式网页在读到 include 的档案时，才将它读进来。这种方式，可以把程式执行时的流程简单化。错误产生警报。
include_once:此行为和include()语句类似，唯一区别是如果该文件中的代码已经被包含了，则不会再次包含。如同此语句名字暗示的那样，只会包含一次。
13. What function would you use to redirect the browser to a new page?
1. redir()