calpr.py

"""
Print the calendar for a month
(without using the Python 'calendar' module).

Limitations: Treats February as always having 28 days. 

Author: Austin Dayton, Mark Poliquin 
Consulted with Mark on printing full and partial weeks. Much help on printing weeks from
GTF (name unknown at time of submission, in office hours with Anna on 1/15).
"""

import sys      # For command-line arguments 
import datetime # To determine what day of week a month
				# begins on.  
# Note: For this project, module calendar
# is not permitted.  It basically has a function
# to do the whole assignment in one line. 

USAGE = """
Usage:  python3 calpr.py 12 2013
  where 12 can be replaced by any month 1..12
  and 2013 can be replaced by any year 1..2100
"""

if len(sys.argv) != 3:
	print(USAGE)
	exit(1)
	       
month = int(sys.argv[1])
year = int(sys.argv[2])

MONTHLEN = [ 0, # No month zero
	31, # 1. January
	28, # 2. February (ignoring leap years)
	31, # 3. March
	30, # 4. April
	31, # 5. May
	30,	# 6. June
	31, # 7. July
	31, # 8. August
	30, # 9. September
	31, #10. October
	30, #11. November
	31, #12. December
	]


# What day of the week does year,month begin on? 
a_date = datetime.date(year, month, 1)
starts_weekday = a_date.weekday()
## a_date.weekday() gives 0=Monday, 1=Tuesday, etc.
## Roll to start week on Sunday
starts_weekday = (1 + starts_weekday) % 7  


month_day = 1   			## Next day to print
last_day = MONTHLEN[month]  ## Last day to print

print(" Su Mo Tu We Th Fr Sa")
###
###  The first (perhaps partial) week
###
for i in range(7):
	if i < starts_weekday :
		print("   ", end="")
	else:
		# Logic for printing one day, moving to next
		print(format(month_day, "3d"), end="")
		month_day += 1
print() # Newline

###print full weeks
while month_day <= (last_day-7):
	for i in range(7):
		# Logic for printing one day, moving to next
		print(format(month_day, "3d"), end="")
		month_day += 1
	print()

##while days remain, print each day
while month_day <= last_day:
	print(format(month_day, "3d"), end="")
	month_day += 1
print()