Shahd Moustafa

// Stack Using Linked List Implementation.cpp "Using Pointer"
// Val1->Val2->...Val15->Null
// Val + Pointer = Node
#include <iostream>
using namespace std;

// To Accommodate More Than One Data Type
template <class T>
class Stack
  {
  // Create (Node) As A struct
  struct Node {

  T Val;
  // Create Pointer (Next) Points On Node
  Node* Next;
  };
  Node* Top, * X;

  public:
  // Empety Constaractor To Initialize (Top) As NULL
  Stack() {
  Top = NULL;
  }

  // Create Add Function To Add New Element
  void Add(T val) {

  //*Ptr As Pointer Because It Is Linked Stack
  Node* Ptr = new Node;// Use (new) Node
  if (Ptr == NULL)
  cout << "Stack Add Cannot Allocate Memory";
  else{
  // Assigning The Value To The Pointer
  Ptr->Val = val;// Use (->) Because We Are Dealing With Pointer
  Ptr->Next = Top;
  Top = Ptr;
  }
  }

  // To Check Stack Is Empety Or No
  bool CheckIsEmpety() {
  // Case Top == NULL That's Mean The Stack Is Empety
  return Top == NULL;
  }

  // To Erase The Elemets
  void Erase() {
  if (CheckIsEmpety()) {
  cout << "Stack Is Empety";
  }
  else {
  // Create Temporary Pointer Points To *Top
  Node* Temp = Top;

  // To Move Top A Step Down
  Top = Top->Next;

  // Make The Temporary Pointer NULL
  Temp = Temp->Next = NULL;

  // Then Delete Temp
  delete Temp;
  }
  }

  // To Save Temp Value's Before Delete It
  void Save(T&SaveValue) {
  if (CheckIsEmpety()) {
  cout << "Stack Is Empety";
  }
  else {
  // To Save Top Value Before Delete It
  SaveValue = Top->Val;
  cout << "Save Value : " << SaveValue;
  }
  }

  // To Get Top Element
  void GetTop(T&Value) {
  if (CheckIsEmpety())
  cout << "Stack Is Empety";
  else
  Value = Top->Val;
  cout << "\nThe Top Element : " << Value << "\n";

  }

  // Print Function
  void Print() {
  X = Top;
  cout << "\nElements In The Stack : [";
  while (X != NULL)
  {
  cout << X->Val << " ";
  X = X->Next;
  }
  cout << "]\n";
  }

  };

  int main()
  {
  Stack<int> obj;

  // Add Some Values
  obj.Add(15);
  obj.Add(70);
  obj.Add(23);
  // Print The Values
  obj.Print();
  //Get The Top
  int k = 0;
  obj.GetTop(k);
  obj.Save(k);
  // After Remove Top Element
  obj.Erase();
  // Print After Remove Top Element
  cout << "\nAfter Remove Top Element";
  obj.Print();

}