pyMovieDuration

# An exercise in OOP and Time calculations
# Given a Movie's start time and duration, compute and print the end time.
# We can assume the movie will end before midnight!

# *** Dec 20th: I moved the definition of the duration() method to the end of the class
# just to prove that it can be referred to within the class before it is defined. No problem.

class Time(object):             # this defines a "prototype" of an object

    def start(self, hh, mm, ss):        # This is another 'method' within the Time class
        # Establish the start time of the movie in seconds.
        # We can do it in a simple manner by adding the start time to a zero base time
        # (as we already have such a function)
        self.seconds = 0                # Establish a zero base starting time
        self.duration(hh, mm, ss)       # Add the start time to the base (so base now equals start)

    def calculate(self):                # This is a third 'method' within the Time class
        # convert the end time (which is in seconds) to hours, minutes, seconds
        mm, ss = divmod(self.seconds, 60)       # divmod() is a built-in Python function that ...
        hh, mm = divmod(mm, 60)                 # ... computes the quotient and remainder of a division
        # Convert the hours minutes and seconds to strings, with zero-fill
        self.endtime = str(hh).zfill(2) + ':' + str(mm).zfill(2) + ':' + str(ss).zfill(2)

    # We'll start by defining a 'method' that adds a time in hours, minutes, seconds
    # to a base time held in seconds only
    def duration(self, hh, mm, ss):
        self.seconds += hh * 3600       # add 3600 seconds for every hour
        self.seconds += mm * 60         # and 60 seconds for every minute
        self.seconds += ss              # finally add in the seconds

movie = Time()                  # Instantiate an object called 'movie' of class 'Time'
movie.start(21, 30, 30)         # Pass the movie start time to our movie object
movie.duration(1, 50, 40)       # Pass the movie duration to our movie object
movie.calculate()               # Call the movie method that computes the end time
print(movie.endtime)            # Print the result

# 23:21:10