[C++] new & delete

new

 

int *ptr = new int;
int *arr = new int[10];

 

new is a keyword that replaces malloc() in C++.

(Of course you can use malloc(), if you need.)

Disadvantage in using malloc() is that you must allocate memory in size of bytes.

And you need proper casting ,because it's default return type is void.

 

int *ptr = new int;
int &ref = *ptr;
ref=20
cout<<*ptr<<endl;  //result : 20 

This sentence is meaningful, because it accesses heap area without pointer.

 

 

 

 

 

 

delete

delete ptr;
delete []arr;

delete is a keyword that replaces free() in C++.

If you delete 'arr' without '[]' only the first element of array gets deleted.

 

 

 

 

 

 

 

 

 

 

Accessing heap memory

 

 

int *ptr=new int;
int &ref=*ptr;
ref=20;
cout<<*ptr<<end;

 

Now you now how to access heap memory with reference as you see.