php 類的初始化(1/2)
Jun 08, 2016 pm 05:26 PM?代碼如下 | 復制代碼 |
class child $parent = new parent('hispanic'); |
php教程中是通過類來完成信息封裝的,在php中定義類的語法是:
class class_name // 在面向?qū)ο缶幊填愔?,習慣上類的第一個字符為大寫,并且必須符合變量的命名規(guī)則。
{
//函數(shù)與變量的集合
}
?>
在定義類時你可以按自已的喜好的格式進行定義,但最好能保持一種標準,這樣開發(fā)起來會更有效些。
數(shù)據(jù)成員在類中使用"var"聲明來定義,在給數(shù)據(jù)成員賦值之前,它們是沒有類型的。一個數(shù)據(jù)成員可以是一個整數(shù),一個數(shù)組,一個相關(guān)數(shù)組(associative array)或者是一個對象。
下面是一個類定義的實際例子:
?代碼如下 | 復制代碼 |
class student { var $str_name; //姓名 var $str_sex; //性別 var $int_id; //學號 var $int_english; //英語成績 var $int_maths; //數(shù)學成績 } ?> |
這是一個很普通定義類的簡單例子,用于顯示學生的學習成績,類名為student,student類包涵了一個學生的基本屬性:姓名、性別、學號、英語成績和數(shù)學成績。
function我們稱之為在類中被定義的函數(shù),在函數(shù)中訪問類成員變量時,你應(yīng)該使用$this->var_name,其中var_name 指的是類中被聲明的變量,否則對一個函數(shù)來說,它只能是局部變量。 我們先定義一個input()的函數(shù),用來給實例中的對象賦以初值:
?代碼如下 | 復制代碼 |
function input ( $name, $sex, $id, $englis, $maths) { $this->str_name=$name; $this->str_sex =$sex; $this->int_id =$id; $this->int_englis=$english; $this->int_maths=$maths; } |
現(xiàn)在我們再定義一個叫“showinfo()”的函數(shù),用于打印學生的基本情況:
?代碼如下 | 復制代碼 |
function showinfo() //定義showinfo()函數(shù) ”); ”); ”); ”); ”); |
而定義好的類則必須使用new關(guān)鍵詞來生成對象:
$a_student=new student;
例如我們要為一個名為$wing的對象創(chuàng)建實例,并進行賦值,可以使用下面的代碼:
$wing =new student; //用new關(guān)鍵詞來生成對象
$wing ->input (“wing”,”男”,33,95,87);
//分別輸入wing的姓名、性別、學號、英語成績、數(shù)學成績,其中姓名和性別是字符型變量,所以需要用雙引號,其它為數(shù)值型變量則不需要。?

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