/* Author: Paul Caron, alias ChillPill About: Easy implementation of smart pointers. What are smart pointer? -They are a wrapper object around a pointer. When the smart pointer object goes out of scope, the object pointed by the wrapped pointer gets deleted when the smart pointer's destructor is called. So no need to manually call delete for every objects created on the heap. */ #include using namespace std; struct A{ char c='z'; explicit A(){cout<<"A created"< class smart_ptr { T* p=nullptr; public: explicit smart_ptr(T* p):p(p){} smart_ptr(smart_ptr& other){ this->p=other.p; other.p=nullptr; } ~smart_ptr(){delete p;} T* get(){return p;} T* operator->(){return p;} T& operator*(){return *p;} void swap(smart_ptr & p2){ T* temp=p; p=p2.p; p2.p=temp; } T* release(){ T* temp=p; p=nullptr; return temp; } void reset(T* new_p){ delete p; p=new_p; } }; //specialization for arrays template class smart_ptr { T* p=nullptr; public: explicit smart_ptr(T p[]):p(p){} ~smart_ptr(){delete [] p;} T* get(){return p;} T& operator[](size_t i){return *(p+i);} void swap(smart_ptr & p2){ T* temp=p; p=p2.p; p2.p=temp; } T* release(){ T* temp=p; p=nullptr; return temp; } void reset(T new_p[]){ delete [] p; p=new_p; } }; //this make_sp function is taken from make_unique possible implementation https://en.cppreference.com/w/cpp/memory/unique_ptr/make_unique template smart_ptr make_sp(Args&&... args) { return smart_ptr (new T( forward (args)...)); } int main() { smart_ptr p(new A()); p.get()->hi(); (*p).c='p'; p->hi(); //swaping pointers smart_ptr p2(new A()); p.swap(p2); p->hi(); p2->hi(); //releasing pointer A* rp=p.release(); //reset pointer p.reset(new A()); smart_ptr q(new A[3]); q[0].c='a'; q[1].c='b'; q[2].c='c'; q[0].hi(); q[1].hi(); q.get()[2].hi(); cout<('x'); x->hi(); auto y(x); y->hi(); delete [] rpq; delete rp; //delete the released pointers cout<<"deleted released ptrs"<

#DesignPatterns - custom smart pointer operator * [] -> overload