Question

I have nested iterator in my custom stack template class.
The problem I get now is that my nested iterator’s constructor does not match when I create an iterator for my stack in the main. I wonder what the problem could be.

template <class T>
class stack
{
private:
    int top;
    T st[100];

public:
    class my_iterator
    {
    public:
        my_iterator() : list(0), curr(0) {};

    private:

        stack<T> list;
        int curr;
    };

//publics in stack class
public:
    stack();
    void push(T i);
    T pop();
    void print();
    bool is_full();
    my_iterator begin() {};

};

and I create the iterator for stack with the following line in main

stack<double>::my_iterator it;

Answer 1

It looks like you forgot a *:

class my_iterator
{
public:
    my_iterator() : list(0), curr(0) {};
private:
    stack<T>* pStack; // Pointer to a stack.
    int curr;
};

Of course, you need more members (including better constructors) for the class. But this should at least allow you to create default iterators that do not point to any stack in particular.