Question

Python 3

Here is my question.

In clock.py, define class Clock which will perform some simple time operations. Write an initializer function for Clock that will take three arguments from the user representing hour (in 24-hour format), minutes, and seconds. Each of these parameters should have a reasonable default value. You should check that the provided values are within the legal bounds for what they represent and raise a ValueError if they are not.

if error_condition:
    raise ValueError("Descriptive error message")

Write instance method __str__ that will print the time in a nicely formatted fashion when the user calls print(clock_instance). The result of the __str__ method should primarily be readable.

>>> my_clock = clock.Clock(12, 34, 56)
>>> print(my_clock)
12:34:56
>>> my_clock = clock.Clock(1, 2, 3)
>>> print(my_clock)
01:02:03

Write instance method __repr__. The result of the __repr__ method should primarily be, above all, unambiguous. __repr__ should return a string that is intended more as a debugging aid for developers than anything else. And for that it needs to be as explicit as possible about what this object is. That’s why you’ll get a more elaborate result calling repr() on the object. __repr__'s output often the full module and class name:

>>> my_clock = clock.Clock(8, 56, 48)
>>> repr(my_clock)
'clock.Clock(8, 56, 48)'

Write instance method __add__ that will add the value of another Clock instance to the current one. Create and return a new Clock instance with the computed values.

>>> clock1 = clock.Clock(1, 34, 55)
>>> clock2 = clock.Clock(1, 7, 10)
>>> clock3 = clock1 + clock2
>>> print(clock3)
'02:42:05'

Add a class method, str_update, that will take as an argument a string in the form hh:mm:ss. In the method, parse the string into three integers and then set the Clock's time to the new values.

>>> my_clock = clock.Clock(8, 34)
>>> myclock.str_update("17:15:52")
>>> print(my_clock)
'17:15:52'

Answer 1

Python code

clock.py

class Clock:
  
   # constructor to initialize time values
   def __init__(self, hours=0, minutes=0, seconds=0):

       count = 0
       # check lower and upper bound for hours value
       if(hours>=0 and hours<=23):
           count+=1
       else:
           # raise value error
           raise ValueError("Hours should be between 0 and 23")

       # check lower and upper bound for minutes value
       if(minutes>=0 and minutes<=59):
           count+=1
       else:
           # raise value error
           raise ValueError("Minutes should be between 0 and 59")
  
       # check lower and upper bound for seconds value
       if(seconds>=0 and seconds<=59):
           count+=1
       else:
           # raise value error
           raise ValueError("Seconds should be between 0 and 59")

       if(count == 3):
           self.hours = hours
           self.minutes = minutes
           self.seconds = seconds

   def __str__(self):
      
       # return time in hh:mm:ss format
       return format(str(self.hours), "0>2")+":"+format(str(self.minutes), "0>2")+":"+format(str(self.seconds), "0>2")

   def __repr__(self):
      
       # return clock class object
       return "'clock.Clock(%s, %s, %s)'" % (str(self.hours), str(self.minutes), str(self.seconds))

   def __add__(self, other):

       # add seconds of object 1 and object 2
       seconds = self.seconds + other.seconds

       # add minutes of object 1 and object 2 and add seconds/60
       minutes = self.minutes + other.minutes + (seconds//60)
      
       # assign seconds%60 to seconds
       seconds = int(seconds%60)

       # add hours of object 1 and object 2 and add minutes/60
       hours = self.hours + other.hours + (minutes//60)

       # set minutes to minutes%60
       minutes = int(minutes%60)

       return Clock(hours, minutes, seconds)

   def str_update(self, string):
      
       # split the time string by :
       string = string.split(":")
      
       # update hours, minutes, and seconds values of the clock object
       self.hours = int(string[0])

       self.minutes = int(string[1])

       self.seconds = int(string[2])

main.py

# import clock
import clock

# create object clock1 for Clock class
clock1 = clock.Clock(1, 34, 55)

# create object clock2 for Clock class
clock2 = clock.Clock(1, 7, 10)

# add values of objects clock 1 and clock 2
clock3 = clock1 + clock2

# print value of resultant clock object
print(clock3)

# create object my_clock for Clock class
my_clock = clock.Clock(8, 34)

# update the value of clock object by passing string
my_clock.str_update("17:15:52")

# print the updated value of the clock object
print(my_clock)

# create object my_clock for Clock class
my_clock = clock.Clock(8, 56, 48)

# print object
print(repr(my_clock))

Sample Input/Output