Class part2

14.3

Implementing member functions in class definitions inline

The functions implemented in the definition of a class are inline functions ;
As shown below ：

public:
     void addhour(int tmphour)
     {
    
        Hour=Hour+tmphour;
     }

At the end of a member function const

If you add const Then the member variable value cannot be modified ;

void noone()const
{
    
   Hour+=10;  // error , Changed member variables ;
}

mutable

use mutable Character to modify member variables, you can modify member variables

mutable int myHour;
void noone()const
{
    
   myHour+=10;  // No mistake. ;
}

this The pointer

this Understanding of pointer ：
When calling a member function , The compiler is responsible for passing the address of the object calling the function to a formal parameter this in ;

Some related statements ：

• this Can only be used in member functions ; Global functions or static functions cannot be used ;
• this It's a pointer constant , Always point to this object , Can't point anywhere else ;

14.4

Class related nonmember functions

If you want to call a non member function in a class , It can take the form of ：

// Ordinary function 
void func(xx &xcc)
{
    
.....

}

In class xx.h In file

void func(xx &xcc)

default Key words and delete

default keyword
Add to the class definition =default keyword , Then the default constructor can be generated ;
for example ：

Time()=default;

delete
If added delete Disable a function ;

Time'()=delete;

14.5 copy constructor

1. The first parameter of the class's construction parameter is the class type reference , If there are additional parameters , Then these parameters must have default values , It will be automatically called by the system at a specific time ;
   Example `

Time(const Time&tmptime ,int a=3);

2. If you don't define a copy constructor , Then the system will automatically synthesize a copy constructor