Constructor and naming method

Constructor:

1. the constructor has no return value. The function name and class name must be the same;

2. After the method is called, all memory allocated to the stack will disappear;

The memory in the stack disappears immediately after the method is called; the memory in the corresponding stack needs to wait for the garbage collection mechanism;

3. If no constructor is specified, an empty method is added by default, and the class name (){};

Naming rules:

1. The first letter of the class name is capitalized;

2. The method name variable name starts with lowercase letters;

3. Use the camper name method;