///////////////////////////////////////////////////////////////////////////////////////////////
//                                                                                           //
//                                CSE 428 - SPRING 2001                                      //
//                                                                                           //
//                              Solution of Assignment #3                                    //
//                                                                                           //
//                                    file S3.C                                              //
//                                                                                           //
///////////////////////////////////////////////////////////////////////////////////////////////


// #include "A3_code_stack.C" // Original code provided for the assignment

#include "S3_test.C"          // Code for testing the solutions of the students

///////////////////////////////////////////////////////////////////////////////////////////////

stack1::~stack1()
{
   while (top != NULL) {
      pop();
   }
} 

void stack1::pop()
{
   element* tmp = top;
   if (top != NULL) {
      top = top->next;
      delete tmp;
   }
   else 
      cout << "Error: pop() on an empty stack";
}
        
int stack1::position(int x)
{
   element* tmp = top;
   bool found = false;
   int pos = 0;

   for(; tmp != NULL && !found; pos++) {
        found = (tmp->info == x);
        tmp = tmp->next;
   }

   if (found)
      return pos;
   else
      return 0; 
}

///////////////////////////////////////////////////////////////////////////////////////////////

void stack2::pop()
{
   stack2* tmp = next;
   if (tmp != NULL) {
      next = next->next;
      tmp->next = NULL;  //Necessary to avoid recursive calls of the stack2 destructor 
      delete tmp; 
   }
   else 
   cout << "Error: pop() on an empty stack";
}
        
int stack2::position(int x)
{
   stack2* tmp = next;
   bool found = false;
   int pos = 0;

   for(; tmp != NULL && !found; pos++) {
        found = (tmp->info == x);
        tmp = tmp->next;
   }

   if (found)
      return pos;
   else
      return 0; 
}

///////////////////////////////////////////////////////////////////////////////////////////////