PHP编程：为您详解PHP开辟东西的利用与剖析
培训的第二阶段，开始了PHP语言语法结构和应用的学习。 有一段工夫一向利诱于PHP中援用的传递，后来查手册及C源法式，并重复测试，大致对援用传递在内存中的形式有了必定的懂得，后来为了加深印象，写了个总结，应当不会有大的成绩――固然这是在PHP4中，在今后的版本中能够会有变更。事先写总结的时分，想熬炼一下英语，因而就对付了一篇。不外自己英语欠好，也懒得翻译，归正事先想本人看得懂就好了。明天血汗来潮，俄然感觉还蛮有效的，因而在这里现丑了，请人人斧正。那位看得懂的协助翻译一下吧，我没空了。<P><?php
/*
filename: SetGetTest.php
comment on assignment by value and referrence
assuming $var is a varialbe, its handle(pointer) is named as *var,
and its content is named as @var
the memory area of @var is referred by *var, if the *var is the same,
then the memory areas are the same, so *var is just like a pointer.
1. when $var = $var1
@var copied from @var1, but in the different memory area,
new *var assigned by the system, pointing to the memory area holding @var
*var and *var1 are different
2. when $var =& $var1,
*var assigned by *var1, and the @var is not assigned or copied,
it is absolutely the same as @var1, and in the same memory area
both *var and *var1 pointing to the memory area, that means they are the same.
passing by referrence
3.
function set1(&$s){
$var =& $s;
}
set1($var1) results:
*var1 passing to the function, and *s is the same as *var1,
then *var is the same as *s, the result is that *var is the same as *var1
and all the contents are the same obviously.
4.
function set2(&$s){
$var = $s;
}
set2($var1) results:
*var1 passing to the function, and *s is the same as *var1,
but when $var = $s executes, from 1. we can see @var is the same as @s,
but *var is different from *s, so @var and @s is not in the same memory area,
while @s and @var1 is sharing the same memory area, also *var1 and *s are the same.
5.
normal function return:
function get(){ return $var1; }
assuming the result is referred by a variable $result.
then @result is copied from @var1 but *result is not the same as *var1
when $var = get();
first you get a variable $result, as I said above, @result is the same as @var1, but *result
is different from *var1, and next $var = $result executes.
As I said in 1., you can find, @var is the same as @result and the same as @var1,
but *var is different from *result AND *var1;
while $var =& get() just means:
*var is the same as *result, so @var and @result are in the same memory area,
but they are still different from those of $var1,
both the memory area of @var1 and *var1,
6.
returning by referrence
function &get(){ return $var1; }
there are two ways to get the result
$var = get(); and $var =& get(); now I will tell the difference
I. $var = get();
the *result is the same as *var1 and so @result and @var1 are the same.
and then $var = $result executes,
*var is not the same as *result, and also different from *var1,
but their contents are the same.
I. $var =& get();
the *result is the same as *var1 and so @result and @var1 are the same.
and then $var =& $result executes,
this means $var and $result are the same, both of @ and *
*/
// the test is the following
function println($s = ""){
print "$s<br>\n";
}
class GetSetTest
{
var $var = null;
function setByRef(&$arg){
$this->var =& $arg;
}
function passByRef(&$arg){
$this->var = $arg;
}
function setByVal($arg){
$this->var = $arg;
}
function &getByRef(){
return $this->var;
}
function getByVal(){
return $this->var;
}
}
$o = new GetSetTest;
println("============ setByRef getByRef =============");
println("-----------------Before change----------------");
$in = "before change";
$o->setByRef($in);
$outByVal = $o->getByRef();
$outByRef =& $o->getByRef();
println("\$in: ".$in);
println("\$outByVal: ".$outByVal);
println("\$outByRef: ".$outByRef);
println("\$this->var: ".$o->var);
println("-----------------After change-----------------");
$in = "after change";
println("\$in: ".$in);
println("\$outByVal: ".$outByVal);
println("\$outByRef: ".$outByRef);
println("\$this->var: ".$o->var);
println();
println("============ setByRef getByVal =============");
println("-----------------Before change----------------");
$in = "before change";
$o->setByRef($in);
$outByVal = $o->getByVal();
$outByRef =& $o->getByVal();
println("\$in: ".$in);
println("\$outByVal: ".$outByVal);
println("\$outByRef: ".$outByRef);
println("\$this->var: ".$o->var);
println("-----------------After change-----------------");
$in = "after change";
println("\$in: ".$in);
println("\$outByVal: ".$outByVal);
println("\$outByRef: ".$outByRef);
println("\$this->var: ".$o->var);
println();
println("============ passByRef getByVal =============");
println("-----------------Before change----------------");
$in = "before change";
$o->passByRef($in);
$outByVal = $o->getByVal();
$outByRef =& $o->getByVal();
println("\$in: ".$in);
println("\$outByVal: ".$outByVal);
println("\$outByRef: ".$outByRef);
println("\$this->var: ".$o->var);
println("-----------------After change-----------------");
$in = "after change";
println("\$in: ".$in);
println("\$outByVal: ".$outByVal);
println("\$outByRef: ".$outByRef);
println("\$this->var: ".$o->var);
println();
/*
以下输入了局是我（夜猫子）私自编纂添加的，次要是为后来人检查便利加在这里，越肉代办，向longnetpro道歉
输入了局：
============ setByRef getByRef =============
-----------------Before change----------------
$in: before change
$outByVal: before change
$outByRef: before change
$this->var: before change
-----------------After change-----------------
$in: after change
$outByVal: before change
$outByRef: after change
$this->var: after change
============ setByRef getByVal =============
-----------------Before change----------------
$in: before change
$outByVal: before change
$outByRef: before change
$this->var: before change
-----------------After change-----------------
$in: after change
$outByVal: before change
$outByRef: before change
$this->var: after change
============ passByRef getByVal =============
-----------------Before change----------------
$in: before change
$outByVal: before change
$outByRef: before change
$this->var: before change
-----------------After change-----------------
$in: after change
$outByVal: before change
$outByRef: before change
$this->var: after change
*/
?>
我先把我自己学习PHP的过程做一下概括： 说php的话，首先得提一下数组，开始的时候我是最烦数组的，总是被弄的晕头转向，不过后来呢，我觉得数组里php里最强大的存储方法，所以建议新手们要学好数组。 为了以后维护的方便最好是代码上都加上注释，“予人方便，自己方便”。此外开发文档什么的最好都弄齐全。我觉得这是程序员必备的素质。虽然会消耗点很多的时间。但是确实是非常有必要的。 首先声明：我是一个菜鸟，是一个初学者。学习了一段php后总是感觉自己没有提高，无奈。经过反思我认为我学习过程中存在很多问题，我改变了学习方法后自我感觉有了明显的进步。 建议加几个专业的phper的群，当然啦需要说话的人多，一处一点问题能有人回答你的，当然啦要让人回答你的问题，平时就得躲在里面聊天，大家混熟啦，愿意回答你问题的人自然就多啦。 本人接触php时间不长，算是phper中的小菜鸟一只吧。由于刚开始学的时候没有名师指，碰过不少疙瘩，呗很多小问题卡过很久，白白浪费不少宝贵的时间，在次分享一些子的学习的心得。 使用zendstdio 写代码的的时候，把tab 的缩进设置成4个空格是很有必要的 首先我是坚决反对新手上来就用框架的，因为对底层的东西一点都不了解，造成知识上的真空，会对以后的发展不利。我的观点上手了解下框架就好，代码还是手写。当然啦如果是位别的编程语言的高手的话，这个就另当别论啦。 使用 jquery 等js框架的时候，要随时注意浏览器的更新情况，不然很容易发生框架不能使用。 多看优秀程序员编写的代码，仔细理解他们解决问题的方法，对自身有很大的帮助。 我要在声明一下：我是个菜鸟！！我对php这门优秀的语言也是知之甚少。但是我要在这里说一下php在网站开发中最常用的几个功能： 本文当是我的笔记啦，遇到的问题随时填充 建议加几个专业的phper的群，当然啦需要说话的人多，一处一点问题能有人回答你的，当然啦要让人回答你的问题，平时就得躲在里面聊天，大家混熟啦，愿意回答你问题的人自然就多啦。 写的比较杂，因为我也是个新手，不当至于大家多多指正。 不禁又想起那些说php是草根语言的人，为什么认得差距这么大呢。 写的比较杂，因为我也是个新手，不当至于大家多多指正。 实践是检验自己会不会的真理。 写js我最烦的就是 ie 和 firefox下同样的代码 结果显示的结果千差万别，还是就是最好不要用遨游去调试，因为有时候遨游是禁用js的，有可能代码是争取结果被遨游折腾的认为是代码写错。 真正的方向了，如果将来要去开发团队，你一定要学好smarty ,phplib这样的模板引擎， 至于模板嘛，各位高人一直以来就是争论不休，我一只小菜鸟就不加入战团啦，咱们新手还是多学点东西的好。
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