One 、 An array of objects

Will have Objects of the same class type An orderly collection constitutes An array of objects .

Definition form of one-dimensional object array :

Class name Object array name [ Constant expression ];

Such as : student stu1[10];

Object array instructions :

1） When creating an object array , Constructor needs to be called . If the object array has 10 Elements , You need to call 10 The secondary constructor .

2） If the constructor has only one parameter , When defining an array, you can directly provide arguments in the initial value list
Such as :student stu1[3] = {67,75,89 };

3） If the constructor has multiple arguments , You cannot provide all arguments directly when defining an array , You should write out the constructor name separately and specify the arguments in parentheses , Call constructors separately , Initialize each element pair .

Such as :student stu1[3]={student(20060101,” Zhang San ”, 67),student(20060102,” Li Si ,75),student(20060101,” Wang Wu ”,75) };

Two 、 Object pointer

        C++ The pointer of is divided into Data pointer 、 A function pointer 、 Data member pointer 、 Member function pointer Four kinds of , and You can't just switch between each other . The first two are C Linguistic , It's called a normal pointer ; The latter two are C++ Specially extended for classes , Called a member pointer . become Member pointer Related to the type of class and the type of member , it Applies only to non static members of a class . Because static class members are not part of any object , So static member pointers can be ordinary pointers .

1> Pointer to object

         When creating objects , The compiling system will allocate a certain storage space for each object , To deposit its members . The starting address of the object memory unit is the pointer of the object .
You can define a pointer variable , The address used to store the object , This is it. Pointer variable to the object .
The definition form of pointer variable pointing to class object :

Class name * Object pointer variable name ;

Such as : student stu;
      student *p = &stu;

You can access objects and their members through object pointers .

Such as : student stu; 
     student *p = &stu;
     p -> num ;  or (*p). num;
     p -> display(); or (*p). display( );

2> A pointer to a member of an object

The members of the object take up storage space , So there are addresses , Can define Pointer variables to object members .

1. Pointer variable definition form pointing to object data member :
Data member type * Pointer variable name ;

Such as : student stu;
      int *p = &stu . num;
2. Pointer to object member function

When defining a pointer to a member function , You must ensure that it matches the type of the function it refers to :
1） Type and number of function parameters .

2） Return type .

3） The type of class .
Pointer variable definition form pointing to object member function :
data type ( Class name :* Pointer variable name )( parameter list );

Such as : void ( student :: *p)（）;
     p= &student :: display;

3> Pointing to the current object this The pointer

When member functions of different objects refer to data members , How to ensure that the specified member is referenced ？
Each member function contains a special pointer , The name of this pointer is fixed , be called this The pointer , It's a pointer to an object of this class , Its value is The starting address of the object where the currently called member function is located .
this Pointer is a Implied pointer , Implicit in In the member function of each class , That is, when a member function is called , All will Automatically generate One this The pointer , It is Passed as a parameter to a member function .
 

#include<iostream>
using namespace std;

class Student
{
private:
	int num;
	string name;
	float score;
public:
	Student()
	{
		num = 2020;
		name = "zhangsan";
		score = 85;
	}
void Print()
{
	cout << "num:" << this->num << endl;
	cout << "name:" << (*this).name << endl;
	cout << "score:" << score << endl;
}
};
int main()
{
	Student stu1;
	stu1.Print();
	return 0;
}