# Author:  James Tam
# Version: July 3, 2014
# Employed named constants for the months instead of unnamed constants

JAN = 1
FEB = 2
MAR = 3
APR = 4
MAY = 5
JUN = 6
JUL = 7
AUG = 8
SEP = 9
OCT = 10
NOV = 11
DEC = 12

# Entering Month separate from day: 
# Once month value is entered it cannot be changed
month = -1
while (month < JAN) or (month > DEC):
    month = int(input("Enter value for month (1 - 12): "))
    if (month < JAN) or (month > DEC):
        print("Month must be a value from 1 - 12")

# Months with 31 days
if (month in (JAN,MAR,MAY,JUL,AUG,OCT,DEC)):
    day = -1
    while (day < 1) or (day > 31):
        day = int(input("Enter value for day (1 - 31): "))
        if (day < 1) or (day > 31):
            print("Day must be a value from 1 - 31")

# Months with 30 days
elif (month in (APR,JUN,SEP,NOV)):
    day = -1
    while (day < 1) or (day > 30):
        day = int(input("Enter value for day (1 - 30): "))
        if (day < 1) or (day > 30):
            print("Day must be a value from 1 - 30")

# Assume Feb always has 29 days
elif (month == FEB):
    day = -1
    while (day < 1) or (day > 29):
        day = int(input("Enter value for day (1 - 29): "))
        if (day < 1) or (day > 29):
            print("Day must be a value from 1 - 29")

print()
print("Birth information")
print("Birth month: %d" %month)
print("Day of birth: %d" %day)