New dynamically allocated Delete frees memory

In C + +, for variables and objects are compiler-allocated at compile-time, for array initialization, can not determine how much memory, it is very likely to cause large open small use case.

New Dynamic Assignment

General format: 1. Pointer variable name =new type identifier;

2. Pointer variable name =new type identifier (initial value);

3. Pointer variable name =new type identifier [number of memory units]; Defining methods for opening arrays

The new operator returns a pointer to a variable of the assigned type.

Delete Frees memory

General format: 1.delete p;

2.delete []p;

Delete the address space of the variable p and release the int memory. --Heap area (priority queue) Delete P is actually meant to remove the target address that P points to, freeing up the memory it occupies, rather than removing the P pointer.

There are two major problems with delete: 1. Memory leaks 2. Repeat release

int* P=new int;

Delete p;

P=null; A good habit of washing your hands after the toilet

Destructors

Destructors for linear tables

1. int* p;

while (Fisrt!=null) {

P=first;

first=first->next;

Delete p;

}

Error Resolution:

int* P=first;

while (P!=null) {

Delete p;

p=p->next;

}

Has released the first address pointed to by P, what exactly does P->next point to? Error!!!

int a=5;

int* P=a;

cout<<*p<<endl; Address content to which P is pointing

cout<<&p<<endl; Address of P itself

cout<<p<<endl; P point to address = = &a

New dynamically allocated Delete frees memory