C + + dynamic memory allocation and release references

New operator

1, pointer variable = new data type, such as: int *p; p=new int;

2, new allocates a piece of memory space from the memory Zhongwei program, and returns the first address pointing to the memory, which is stored in the pointer variable

New

Allocating memory first, making complex types of constructs

Delete

Release

Delete operator

Delete pointer variable, such as: delete P;

(1) Use new to get memory space, must be released with delete

(2) A pointer can only be called once for a delete

(3) The object using the delete operator must be the first address between the memory allocated with new

Note: the free () function allocates memory in C language

New A;

delete []a;

#include <iostream>using namespace Std;void main () {    int *p;    p = new int;    *p = 5;    cout << *p;    Delete p;}

It can be initialized while allocating memory with new. The form of use is:

Pointer variable = new data type (initial value)

For example, the above mentioned

p = new int;

*p = 5;

can also be written

p = new int (5);

Create a variable of data type with new

Pointer variable = new data type [array size];

such as: int *p = new Int[5];

At this point the pointer variable points to the address of the first array element. When assigning an array using new, the initial value cannot be supplied.

Scope operators:

In general, if the global variable has the same name as a local variable, then the local variable has a higher precedence within its scope

The C language specifies that the variable can only be used within the scope of a variable and cannot be used with other scope variables. The scope operator is provided in C + +::, he can specify the scope that is required.

Attention:

Cannot be used:: Access local variables in a function

Scoped operators in the C + + language:: You can also qualify members of a class.

#include <iostream>using namespace std;float a=2.4;            global variable void Main () {    int a = 8;          Local variable    cout<<a<<endl;    cout<<::a<<endl;        ::    }

Reference

References in the C + + language are used to point to the same address using more than two variable names in different parts of the program, do not consume memory space, must be initialized when the reference is declared, and once initialized, no additional values can be assigned to him, and the pointer is different first, the pointer is space, The second pointer declaration can be uninitialized and then once the pointer is assigned, it can also be assigned.

#include <iostream>using namespace Std;void main () {    int num =;    int &ref = num;    Ref + = Ten;    cout<< "num" <<num<<endl;    cout<< "ref" <<ref<<endl;    num + = +;    cout<< "num" <<num<<endl;    cout<< "ref" <<ref<<end;    }

C + + dynamic memory allocation and release references