Input check

string input = "";

long double read(string startMes, string stringError, string dotError) { //Checks variable for correct input (number)
    cout << startMes << ": ";
    getline(cin, input);
    dotCount = 0;
    bool onlyDigits = true;
    string dummy;
    while (!onlyDigits || (dotCount >= 0 && dotCount < 2)) {
        for (int i = input.length() - 1; i >= 0; i--) {
            if (!isdigit(input[i])) {
                if (input[i] == '.') dotCount += 1;
                else onlyDigits = false;

            }
        }
        if (onlyDigits && dotCount < 2) {
            return stod(input.c_str());
        }
        else {
            if (!onlyDigits) { cout << stringError << ", type again: "; }
            else if (dotCount > 1) { cout << dotError << ", type again: "; }
            getline(cin, input);
            onlyDigits = true;
            dotCount = 0;
        }
    }
}