1. Challenge: Implement a Shared Pointer

Implement a shared pointer to an int in a class called SharedPointer. The specification for SharedPointer is given below:

Method	Description	Usage	Exceptions
`SharedPointer()`	A constructor which initialises a `nullptr`.	`SharedPointer sp;`	None
`SharedPointer(int*)`	A constructor which initialises `*this` with `ptr`'s resource.	`int* ptr{new int{42}}; SharedPointer sp(ptr);`	None
`~SharedPointer()`	If `this` is the last `SharedPointer` to the resource owned by `this`, then the resource is destroyed.	`int* ptr{new int{42}}; { SharedPointer sp1(ptr); SharedPointer sp2(ptr); SharedPointer sp3(ptr); } *ptr; // Invalid access.`	None
`int* get()`	Returns the stored pointer.	int* ptr1{new int{42}}; SharedPointer sp(ptr); int* ptr2{sp.get()};	None
`long use_count()`	Returns the number of `SharedPointer` managing `*this`'s resource.	`int* ptr{new int{42}}; SharedPointer sp1(ptr); SharedPointer sp2(ptr); SharedPointer sp3(ptr); sp1.use_count() == 3;`	None
`int& operator*()`	Dereferences the stored pointer in `*this`.	`int* ptr{new int{42}}; SharedPointer sp(ptr); *sp == 42;`	None

2. Challenge: Implement a Shared Pointer (Continued)

Take the SharedPointer class from lab03-1 and extend it with the following specification:

Method	Description	Usage	Exceptions
`SharedPointer(SharePointer const& sp)`	Copy constructor. The use count should increase by 1.	`SharedPointer sp1; SharedPointer sp2(sp1);`	None
`SharedPointer(SharePointer&& sp)`	Move constructor. The use count should not increase.	`SharedPointer sp1; SharedPointer sp2(std::move(sp1));`	None
`SharedPointer& operator=(SharePointer const& sp)`	Copy assignment. The use count should increase by 1.	`SharedPointer sp1; SharedPointer sp2; sp2 = sp1;`	None
`SharedPointer& operator=(SharePointer&& sp)`	Move assignment. The use count should not increase.	`SharedPointer sp1; SharedPointer sp2; sp2 = std::move(sp1);`	None
`friend bool operator==(SharedPointer const& lhs, SharedPointer const& rhs)`	Returns true if the values of the resources owned by `lhs` and `rhs` are the same.	`int* ptr{new int{42}}; SharedPointer sp1(ptr); SharedPointer sp2(ptr); sp1 == sp2; // true`	None
`friend std::ostream& operator<<(std::ostream& os, SharedPointer const& sp)`	Outputs the value of the resource owned by `*this`.	`int* ptr{new int{42}}; SharedPointer sp(ptr); std::cout << sp; // &ptr`	None