Question

My question is pretty simple, I just want to know how to call my operator== function in Stack.cpp using a list function.

Here is what I meant. This is my Stack.h file:

class Stack {
public:
   /**constructors and destructors*/

   Stack();

   Stack(const Stack &S);

   ~Stack();

   void pop();

   void push(int data);

   bool operator==(const Stack &S);

[ .......]

private:
   List<int> stack;

};

Here is my List.h file:

template<class listitem>
class List {
private:
   struct Node {
       listitem data;
       Node* next;
       Node* previous;

       Node(listitem data) :
               next(NULL), previous(NULL), data(data) {
       }
   };

   typedef struct Node* NodePtr;

   NodePtr start;
   NodePtr end;
   NodePtr cursor;

   int length;
public:

........

bool operator==(const List &list);

[.......] }

[........]

template<class listitem>
bool List<listitem>::operator==(const List& list) {
   if (length != list.length)
       return false;
   NodePtr temp1 = start;
   NodePtr temp2 = list.start;
   while (temp1 != NULL) {
       if (temp1->data != temp2->data)
           return false;
       temp1 = temp1->next;
       temp2 = temp2->next;
   }
   return true;
}

[......]

So I already define my functions in List.h and I only need to call my function from List again in my Stack.cpp file. For example from my Stack.cpp:

Stack::Stack(const Stack &S) :
       stack(S.stack) {
}

void Stack::pop() {
   stack.remove_start();
}

[......]

And I don't know how to call my operator== function in Stack.cpp from the List.h like the way above. This is what my guess so far but did not work:

bool Stack::operator==(const Stack &S) {
stack.operator==(S.stack);
}

Thank you

Answer 1

When we wish to make a comparison, such as in an if statement, we use the double equals sign (==).

1)bool operator==(const Stack &S); [ .......]

It means whatever the boolean operator it should be belongs to stack or equal to.

2) bool operator==(const List &list);

Likewise link list also compare with the constructor link list.

and constructor need not to call explicitly. it will call itself when program called first.