#include <iostream>
#include <string>


using namespace std;


template <class TBD>
class Stack 
{
    private:
	
		//class variables
        TBD* stack;
        int count;
        int size;
		
    public:
	
		//constructor
        Stack(int size)
        {
            stack = new TBD[size]; //dynamically create array
            count = 0;
            this->size = size;
        }
		
		//destructor
        ~Stack()
        {
            delete[] stack; //delete dynamic memory use 
            
        }
		
		//add to stack 
        void push(TBD item)
        {
            if (count == size)
            {
                throw overflow_error("Stack is full");
            }
            stack[count] = item;
            count++;
        }
		
		//returns item at top without removing it
        TBD top()
        {
            if (count == 0)
            {
                throw underflow_error("Stack is empty");
            }
            return stack[count-1];
        }
		
		//removes item on top 
        TBD pop()
        {
            if (count == 0)
            {
                throw underflow_error("Stack is empty");
            }
            count = count - 1;
            return count;
        }
		
		//checks if stack is empty
        bool empty()
        {
            return (count == 0);
        }
		
		//getters 
        int getCount()
        {
            return count;
        }
        int getSize()
        {
            return size;
        }
};




int main()
{
	//variable declarations
    string sequence;
    int length;
    int total = 0;
    int convert = 1;
    char temp;
    
    try
	{
		//input binary sequence and get length
		cout << "Please enter a binary sequence: ";
		getline(cin, sequence);
		length = sequence.length();
          
		//create dynamic stack with the same size as the length of the sequence 
		Stack<char> mySequence(length);
            
		for (int x = 0; x < length; x++)
		{
			//verify input and load the stack 
			if (sequence[x] != '1' && sequence[x] != '0')
			{
				throw invalid_argument("Binary sequence must consist of only 0s and 1s");
            }
            else
			{
				mySequence.push(sequence[x]);
			}
		}
        
		for (int x = 1; x <= length; x++)
		{
			//unload the stack and calculate decimal total 
			temp = mySequence.pop();
			if (temp == '0')
			{
				convert = convert * 2;
			}
			else if (temp == '1')
			{
				total = total + convert;
				convert = convert * 2;
			}
			else
			{
				throw invalid_argument("Binary sequence must consist of only 0s and 1s");
			}
		}
		
		//output converted number
		cout << "The decimal version of that binary sequence is: " << total << endl;
	}
	//error catching
	catch(underflow_error &e)
	{
		cout << e.what() << endl;
	}
	catch(invalid_argument &e)
	{
		cout << e.what() << endl;
	}
	catch(...)
	{
		cout << "Unknown error" << endl;
	}
    
    return 0;
}