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