Classes and objects -- encapsulation

C++ Treat everything as an object , Objects with the same properties belong to a class .

The meaning of encapsulation is ： Treat attributes and behaviors as a whole

And C The middle structure is similar to .
A class is divided into three parts ： Access right ; attribute ; Behavior
You need to create the corresponding object in the main function
Attributes and behaviors are also collectively referred to as members
attribute = Member attribute = Member variables Behavior = Member functions = Member method

class student {
    
	
	public:								// Access right  
	
	string  s_name;						// attribute  
	string 	s_number;
	
	void writname(string n_name){
    
		s_name=n_name;
	}	
	void writnum(string n_num){
    	
		s_number=n_num;					// Behavior  
	}
	void showstu() {
    
		cout <<" full name ："<<s_name<<endl;
		cout <<" Student number ："<<s_number<<endl;
	}
	
};


int main() {
    
	student a1;
	a1.writname(" Bloom ha "); 
	a1.writnum("18203154");
	a1.showstu();
	return 0; 
}

The second meaning of encapsulation ： Access right

The permissions of all members are divided into three categories

1. Public authority public Member classes can access , You can access
2. Protection rights protected Member classes can access , No access outside of class （ Then inheritance will learn ） The son can visit
3. Private rights private Member classes can access , No access outside of class （ The son can't visit ）

class And struct

struct The default permission for is public
class The default permission for is private

Privatizing member properties is a bit ：

1. You can control the read and write permissions by yourself
2. Write permission can detect the validity of data
   This is a struct Structural variables are incomparable ,struct Anyone can modify all the variables at will , And the operation on the structure needs to rewrite a function , Complicate the code .