из автомата в код

#include <iostream>
#include <fstream>
//3X1^2*X2^1*X3^7-2X1^1*X2^2*X3^3+S(2X1)-4C(2X1);X1^2-2X1^1+3X1^0;S(2X1)-4C(2X1)//
using namespace std;
int main()
{
    char x;
    bool b = true;
    int q = 1, n;
    ifstream f("Text.txt");
    while (f.peek() != EOF && b == true)
    {
        f >> x;
        cout << x;
        switch (q)
        {
        case 1:
            if (x >= '0' && x <= '9')
            {
                q = 2;
            }
            else if (x == 'X')
            {
                q = 3;
            }
            else if (x == 'S' || x == 'C')
            {
                q = 6;
            }
            else b = false;
            break;
        case 2:
            if (x == 'X')
            {
                q = 3;
            }
            else if (x == 'S' || x == 'C')
            {
                q = 6;
            }
            else b = false;
            break;

        case 3:
            if (x >= '0' && x <= '9')
            {
                q = 4;
            }
            else b = false;
            break;

        case 4:
            if (x == '^')
            {
                q = 5;
            }
            else b = false;
            break;


        case 5:
            if (x >= '0' && x <= '9')
            {
                q = 11;
            }
            else b = false;
            break;


        case 6:
            if (x == '(')
            {
                q = 7;
            }
            else b = false;
            break;


        case 7:
            if (x >= '0' && x <= '9')
            {
                q = 8;
            }
            else b = false;
            break;


        case 8:
            if (x == 'X')
            {
                q = 9;
            }
            else b = false;
            break;


        case 9:
            if (x >= '0' && x <= '9')

            {
                q = 10;
            }
            else b = false;
            break;


        case 10:
            if (x == ')')
            {
                q = 11;
            }
            else b = false;
            break;


        case 11:
            if (x == '+' || x == '-' || x == ';')
            {
                q = 1;
            }
            else if (x == '*')
            {
                q = 2;
            }
            else b = false;
            break;
        }

    }
    cout << endl;
    if (b )
        cout << "all right!!";
    else
        cout << "error";
    cout << endl;
    system("pause");
    return 0;
}