How to understand the php construction method

What is a constructor method

The constructor method is a special method of a class, its main function is to complete the initialization of new objects.

Features:

1. No return value

2. When creating a new object, the system will automatically call the constructor of the class Complete the initialization of the new diagonal

    语法:
    php5:        修饰符 function __construct()
                        {
                            //code
                        }
    php4:        修饰符 function 类名()
                        {
                            //code
                        }

Note:
1. PHP5 supports both. If both construction methods exist at the same time, the first one is preferred

2. A class has an empty constructor without parameters by default. Once a constructor is customized, the default constructor will be overwritten, so a class has and only one constructor.

3. A class can only have one constructor. (It cannot be overloaded)

4. The default access modifier of the constructor is public.

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