ДЗ №1 (вещественная запись)

#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    int q = 1;
    char x;
    ifstream f("Text2.txt");
    while ((f.peek() != EOF) && q)
    {
        f >> x;
        switch (q)
        {
        case 1: {
            if ((x == '+') || (x == '-'))
                q = 2;
            else
                q = 0;

            break;
        }
        case 2: {
            if (!(x >= '0' && x <= '9'))
            {
                if (x == '.')
                    q = 3;
                else
                    q = 0;
            }

            break;
        }
        case 3: {
            if (!(x >= '0' && x <= '9'))
            {
                if (x == 'E' || x == 'e')
                    q = 4;
                else
                    q = 0;
            }

            break;
        }
        case 4: {
            if ((x == '+') || (x == '-'))
                q = 5;
            else
                q = 0;

            break;
        }
        case 5: {
            if (!(x >= '0' && x <= '9'))
                q = 0;
            else q = 6;

            break;
        }
        case 6: {
            if (!(x >= '0' && x <= '9'))
                q = 0;

            break;
        }
        }
    }
    if (q == 6)
        cout << "YEeES" << endl;
    else
        cout << "NO" << endl;
    system("pause");
    return 0;
}