What is the difference between pointers and references in c++?

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Pointers stores address of variable but references refers an existing variable with another name.

and const int *const ptr

Reference
1) References are used to refer an existing variable in another name.
2) References cannot have a null value assigned.
3) A reference variable can be referenced by pass by value.
4) A reference shares the same memory address with the original variable but also takes up some space on the stack.
ETC


Pointer(*)
1) Pointer are used to store address of variable.
2) Pointer can be NULL.
3) A pointer can be referenced but pass by reference.
4) A pointer has its own memory address and size on the stack.
ETC