Checks does the input var is number

int isValidNumber()
{
        int number;
        number = 0;
        cin >> number;

        if (cin.fail())
        {
                cin.clear();
                cin.ignore(10000, '\n');
                cout << "You have entered an invalid number.";
                return 0;
        }

        else
        {

                if (number <= 0)
                {
                        cout << "You have entered a negative number.";
                        return 0;
                }
                else
                {
                        return number;
                }
        }




}