/* Returns the number of days in month, in the given year.
   Input: month is an integer between 1 and 12.
          year is a legal year (a non-negative integer).
   Output: The number of dayns in month in the given year. An integer.
*/

int daysInMonth(int month, int year){
  int numberOfDays;
  switch(month){
    case 1: case 3: case 5: case 7: case 8: case 10: case 12: 
      numberOfDays = 31; break;
    case 4: case 6: case 9: case 11: 
      numberOfDays = 30; break;
    case 2:
      if (isLeapYear(year)) numberOfDays = 29; 
      else numberOfDays = 28; break;
    default: exit(-1);  break;
  }
  return numberOfDays;
}