NonPrimitivePDA

// MPAuto20.cpp: определяет точку входа для консольного приложения.
//

#include "stdafx.h"
#include <deque>
#include <string>
#include <iostream>
#include <vector>

using namespace std;

class nonPrimitivePA
{
private:
    int state;
    vector<char> memory;
    deque<char> output;
public:
    nonPrimitivePA()
    {
        state = 1;
        memory.empty();
        output.empty();
    }
    void push(char let)
    {
        memory.push_back(let);
    }
    int parse(deque<char>& txt)
    {
        while (txt.size() != 0)
        {
            if (state == 1)
            {
                if (memory.empty())
                {
                    switch (txt[0])
                    {
                    default: break;
                    case '0': push('A'), txt.pop_front(); break;
                    case '1': return 0;
                    case '\0': return 0;
                    }
                }
                else if (memory.back() == 'A')
                {
                    switch (txt[0])
                    {
                    default: break;
                    case '0': memory.pop_back(), push('B'), txt.pop_front(); break;
                    case '1': return 0;
                    case '\0': return 0;
                    }
                }
                else if (memory.back() == 'B')
                {
                    switch (txt[0])
                    {
                    default: break;
                    case '0': push('A'), txt.pop_front(); break;
                    case '1': state = 2; break;
                    case '\0': return 0;
                    }
                }
            }
            else if (state == 2)
            {
                if (memory.empty())
                {
                    switch (txt[0])
                    {
                    default: break;
                    case '0': return 0;
                    case '1': state = 3; break;
                    case '\0': return 0;
                    }
                }
                else if (memory.back() == 'C')
                {
                    switch (txt[0])
                    {
                    default: break;
                    case '0': return 0;
                    case '1': memory.pop_back(), push('D'), txt.pop_front(); break;
                    case '\0': return 0;
                    }
                }
                else if (memory.back() == 'D')
                {
                    switch (txt[0])
                    {
                    default: break;
                    case '0': return 0;
                    case '1': memory.pop_back(), txt.pop_front(), output.push_front('1'); break;
                    case '\0': return 0;
                    }
                }
                else if (memory.back() == 'B')
                {
                    switch (txt[0])
                    {
                    default: break;
                    case '0': return 0;
                    case '1': memory.pop_back(), push('C'), txt.pop_front(); break;
                    case '\0': return 0;
                    }
                }
            }
            else if (state == 3)
            {
                switch (txt[0])
                {
                default: break;
                case '0': return 0;
                case '1': output.push_front('0'), txt.pop_front(); break;
                case '\0': return 1;
                }
            }
        }
    }
    void getResult()
    {
        for (int i = 0; i < output.size(); i++)
        {
            cout << output[i];
        }
    }
};


int main()
{
    deque<char> input;
    string txt;
    cin >> txt;
    int i = 0;
    while (txt[i] != '\0')
    {
        input.push_back(txt[i]);
        i++;
    }
    input.push_back(txt[i]);

    nonPrimitivePA *obj = new nonPrimitivePA();
    if (obj->parse(input))
        obj->getResult();
    else
        cout << "Incorrect\n";

    return 0;
}