C uses malloc() and calloc() function to allocate memory dynamically at run time and uses free() function to free dynamically allocated memory. C++ supports these functions and also has two operators new and delete that perform the task of allocating and freeing the memory in a better and easier way.
#include<iostream.h>
#include<conio.h>
class cube
{
public:
cube()
{
cout<<endl<<"Constructor is envoked";
}
~cube()
{
cout<<endl<<"Destructor is envoked";
}
};
void main()
{
cube *p=new cube[3];
delete[] p;
getch();
}
Constructor is envoked
Constructor is envoked
Constructor is envoked
Destructor is envoked
Destructor is envoked
Destructor is envoked
Programmers can dynamically allocate storage space while the program is running, but programmers cannot create new variable names "on the fly", and for this reason, dynamic allocation requires two criteria:
1. Creating the dynamic space in memory
2. Storing its address in a pointer (so that space can be accessed)
Memory de-allocation is also a part of this concept where the "clean-up" of space is done for variables or other data storage. It is the job of the programmer to de-allocate dynamically created space. For de-allocating dynamic memory, we use the delete operator. In other words, dynamic memory Allocation refers to performing memory management for dynamic memory allocation manually.