#include<iostream>

using namespace std;

int main()
{
    const int SIZE = 25;
    char e[SIZE];
    int condition;
    char again;
    
    do
    {
        cout << "Please enter a string of 1 and 0: ";
        cin >> e;                                   //Program will only consider 1 and 0.
        condition = 0;

        for(int i = 0; i <  SIZE; i++)
        {
            if(e[i] == '1')
            {
                if(condition == 0)                  //If state zero, input one moves to state one
                {
                    condition = 1;
                }
                else if(condition == 1)             //If state one, input one moves to state two
                {
                    condition = 2;
                }
                else if(condition == 3)             //If state three, input one moves to state four
                {
                    condition = 4;
                    cout << "String is accepted\n"; //at state four, string is accepted and program terminates
                    break;
                }
            }
            else
            {
                if(condition == 0)                  //If state zero, input zero keeps at state zero
                {
                    condition = 0;
                }
                else if(condition == 1)             //If state one, input zero moves to state zero
                {
                    condition = 0;
                }
                else if(condition == 2)             //If state two, input zero moves to state three
                {
                    condition = 3;
                }
                else if(condition == 3)             //If state three, input zero moves to state zero
                {
                    condition = 0;
                }
            }
        }
        cout << endl;
        cout << "Would you like to enter another string: ";
        cin >> again;
    }while(again == 'y' || again == 'Y');
    
    return 0;
}