#include #include #include template class Stack; template std::ostream& operator<<(std::ostream& os, const Stack& s); template class Stack { public: Stack(); ~Stack(); //add new node to the stack void push(const T& value); //delete node from the stack and return value T pop(); //return value from the head of the stack without deleting node inline T peek() const; //check if the stack is empty, i.e. top of the stack is equal to null inline bool isEmpty() const; //clean all memory allocated for the stack inline void clear(); private: //this struct represent node of the stack struct node { T value; node* next; } *top; friend std::ostream& operator<<<>(std::ostream& os, const Stack& s); }; int main() { using std::cout; using std::endl; Stack s; try { s.push(5); s.push(10); s.push(23); s.push(465); cout << "Stack: " << s << endl << endl; s.clear(); cout << "Stack after cleaning: " << endl << s << endl; } catch(const char *msg) { cout << msg << endl; } return 0; } template Stack::Stack() :top(nullptr) {} template Stack::~Stack() { clear(); } template void Stack::push(const T& value) { node *tmp = new node; tmp->value = value; tmp->next = top; top = tmp; } template T Stack::pop() { if (isEmpty()) { throw "Stack is empty!"; } node *tmp = top->next; T value = top->value; delete top; top = tmp; return value; } template inline T Stack::peek() const { if (isEmpty()) { throw "Stack is empty!"; } return top->value; } template inline bool Stack::isEmpty() const { return !top; } template inline void Stack::clear() { while(!isEmpty()) { pop(); } top = nullptr; } template std::ostream& operator<<(std::ostream& os, const Stack& s) { auto tmp = s.top; while(tmp) { os << tmp->value << " "; tmp = tmp->next; } return os; }

Stack class template