Compound Types--references, pointers

Composite type:

Types defined based on other types (int * p int &d)

A declaration statement consists of a basic data type (base type) followed by a list of declarators. Each declarator names a variable andSpecifies this variable is of a type relative to the basic data type.

Cite:

Another alias for the object

#include using namespace std;int main(){int val = 1024;int &refval = val; //refval and val point to the same address refval is another name for valcout << &val << " " << &refval << endl;int &ival; //Error: reference must be initializedcout << val << " " << refval << endl;return 0;}

General initialization, yesCopy the initial value to the newly created objectin, while reference initialization , the programbinds the reference and its initial value inTogether,

Not a copy, a reference cannot be rebound to another object and must be initialized

1. A reference is not an object, just another alias for an existing object

• Operations on references are operations on objects bound to references
• A reference is not an object so a reference to a reference cannot be defined (int&(&a))

int main(){int val = 1024;int&refval = val;refval = 2048;cout << refval << " " << val << endl;return 0;}

I will not talk about it when I go to practice.

Pointer

A pointer is an address

The declarator is written in the form of *d

int* ip1, *ip2;//ip1 and ip2 are both pointers to int objectsdouble* dp, dp1;//dp is a pointer to a double type object, dp1 is a double type object

Get object address

The pointer stores the address of an object. To get the address of the object, you need to get the address character&

int val = 42;int* p = &val;//p stores the address of val,//p points to a pointer to the variable val

Note:A reference is not an object and cannot take an address, but a pointer is an object that has a pointer reference

Difference between reference and pointer

1. The reference must be initialized, the pointer must not be initialized, it will get a random value
2. A reference cannot rebind an object, while a pointer can be given any object of the same type at any time
3. A reference is not an object, so a reference to a reference cannot be defined, while a pointer can define a secondary pointer
4. The size of the reference is the size of the reference type, and the pointer is always the number of bytes occupied by the address space