So below is my while loop code. Loop is endless when I enter anything other than double for cin. How do I make it so that "cout << " Invalid! Please enter the correct amount. " only comes once and that it asks for cin straight after that.?

```
int main ()

double pWeekdays7am_7pm;

cout << "\n  Please enter the amount of electricity (kWh) produced in the following time        periods. If no electricity was produced, enter \"0\"" << endl << endl;

      cout << "      Monday-Friday (7am-7pm)  ";
      cin >> pWeekdays7am_7pm;
      while (pWeekdays7am_7pm < 0)
        { cout << "  Invalid! Please enter the correct amount.  " ;
          cin >> pWeekdays7am_7pm;

```