# C++

## Pointers

```cpp
// delclaring pointers
int* ptr; // default value 0 when printed 

int var; // live in an address 0xA, think of it as empty container 

int var = 7; // assignment of 7 into the var container

```

* **What is a `Identity Matrix`**
* * A square matrix in which all the elements of the principal diagonal are ones and all other elements are zeros. The effect of multiplying a given matrix by an identity matrix is to leave the given matrix unchanged.
* **What is a `Pointer`:**
  * A variable that stores the memory address as its value. A pointer variable points to a data type (like int or string) of the same type, and is created with the \* operator. The address of the variable you're working with is assigned to the pointer: — [w3schools](https://www.w3schools.com/cpp/cpp_pointers.asp)