Answer to Question #275964 in Python for Chanumi

Question

Write a Python program to check whether a given date is valid date or not and to out put the following.

• If the date is valid then the message “Date is Valid” otherwise the message “Date is Invalid”.

• If the date is a valid date, then the next date.

Hint:

Follow the following steps. (NOTE: You are not allowed to use any Python built-in functions.)

• Get the inputs Year, Month, and Date separately.

• Use selection statements, i.e., if-else statements to check if the Date, Month, and the Year are valid.

• if the date is a valid date, then print the next date (Increment the date).

Sample Test Cases:

Enter the Date Expected Result Next Date

Test Case 1 2020 02 30 Date is Invalid -

Test Case 2 2020 02 29 Date is Valid 01-03-2021

Test Case 3 2021 09 31 Date is Invalid -

Test Case 4 2021 13 01 Date is Invalid -

Test Case 5 2021 08 31 Date is Valid 01-09-2021

Answer 1

def ch_to_int(ch):
  if ch == '0':
    return 0
  if ch == '1':
    return 1
  if ch == '2':
    return 2
  if ch == '3':
    return 3
  if ch == '4':
    return 4
  if ch == '5':
    return 5
  if ch == '6':
    return 6
  if ch == '7':
    return 7
  if ch == '8':
    return 8
  if ch == '9':
    return 9

def digit_to_str(digit):
  if digit == 1:
    return '01'
  if digit == 2:
    return '02'
  if digit == 3:
    return '03'
  if digit == 4:
    return '04'
  if digit == 5:
    return '05'
  if digit == 6:
    return '06'
  if digit == 7:
    return '07'
  if digit == 8:
    return '08'
  if digit == 9:
    return '09'


def is_leap_year(year):
  if year % 4 == 0:
    return True
  if year % 4 == 0 and year % 100:
    return year % 400 == 0

def check_date(year, month, day):
  if year < 0:
    return 'Date is Invalid'
  if month < 1 or month > 12:
    return 'Date is Invalid'
     
  max_day_in_month = -1
  if month in (1, 3, 5, 7, 8, 10, 12):
    max_day_in_month = 31
  elif month in (4, 6, 9, 11):
    max_day_in_month = 30
  elif month == 2:
    if is_leap_year(year):
      max_day_in_month = 29
    else:
      max_day_in_month = 28
  if day < 1 or day > max_day_in_month:
    return 'Date is Invalid'
   
  day += 1
  if day > max_day_in_month:
    day -= max_day_in_month
    month += 1
    if month > 12:
      month -= 12
      year += 1
   
  if month < 10:
    month = digit_to_str(month)
  if day < 10:
    day = digit_to_str(day)
  return 'Date is Valid {}-{}-{}'.format(day, month, year)
   
s = input()
year = 1000 * ch_to_int(s[0]) + 100 * ch_to_int(s[1]) + 10 * ch_to_int(s[2]) + ch_to_int(s[3])
month = 10 * ch_to_int(s[5]) + ch_to_int(s[6])
day = 10 * ch_to_int(s[8]) + ch_to_int(s[9])

print(check_date(year, month, day))