C++ Memory Occupation

Sections of memory

You can create variables/objects on two sections of memory stack or heap.
- Stack creation
  Stack creation is much faster than heap creation, but if variable gets out of scope (once the block within which it is declared is exited) the memory gets freed and we can't access that memory. You can create variable on stack just using type and name.
```
int a = 5; // stack variable
```
  You can also create object on stack
```
class Entity{
private:
    const char* m_name;
public:
    Entity() : m_name("Unknown")
    {
    }
};
 
Entity e1; // stack object
```
  You can also create array on stack;
```
int numbers[5]; // stack array
```
- Heap creation
  Heap variables arent destroyed if they get out of scope, instead you must destroy them manualy or they get destroyed if program ends. Heap allocation is much slower than on the stack. To create heap variables/objects you need to use new keyword and pointers.
```
int* a = new int; // heap allocated variable
```
  Object on the heap
```
class Entity{
private:
    const char* m_name;
public:
    Entity() : m_name("Unknown")
    {
    }
};
Entity* e1 = new Entity(); // heap allocated object
```
  Array on the heap
```
int* numbers = new int[5]; // heap allocated array
```
  To free heap memory you use delete keyword and then variable name
```
 int* a = new int;
 
 delete a;
```
  If you free memory for heap array you will use [] after delete keyword
```
int* numbers = new int[5];
 
delete[] numbers;
```

C++ Memory Occupation

Sections of memory