Python中的简单时钟

Question

I wanted to program a simple clock in python:

class Clock:
    def __init__(self):
        self._hours = 0
        self._minutes = 0

    def gethours(self):
        return self._hours

    def getminutes(self):
        return self._minutes

    def sethours(self, hours):
        self._hours = hours

    def setminutes(self,minutes):
        if self._minutes > 60:
            self._hours = self._hours + 1
            self._minutes = 1
        else:
            self._minutes = minutes

    def tic(self):
        if self._minutes > 58:
            self._hours = self._hours + 1
            self._minutes = 1
        else:
            self._minutes = self._minutes + 1

    minutes = property(getminutes, setminutes)
    hours = property(gethours, sethours)

But when I now wanted to check it with the following code I get an AssertionError at assert(c.hours == i and c.minutes == j)

c = Clock()

assert(c.minutes == 0 and c.hours == 0)

for i in range(24):
    assert(c.hours == i)
    for j in range(60):
        assert(c.hours == i and c.minutes == j)
        c.tic()

assert(c.minutes == 0 and c.hours == 0)

Answer 1

Here is a fixed rewriting, using the same test. The setters take care of setting correctly the values for hours and minutes (though hours' setter does not manage correctly adding more than one day, but this is easy to add based on the same model as for minutes).

Then tic() is only a shortcut for adding one minute.

Comment out the print statement to remove all hours:minutes.

Note: I've turned Clock to a "new style" class object, that allow to use property decorators and makes everything more readable (this not necessary for python3, but necessary to let the same code work also in python2).

class Clock(object):
    def __init__(self):
        self._hours = 0
        self._minutes = 0

    @property
    def hours(self):
        return self._hours

    @property
    def minutes(self):
        return self._minutes

    @minutes.setter
    def minutes(self, value):
        if value >= 60:
            # Take care, if one adds more than one hour, to
            # take the extra hours into account too:
            self.hours += value // 60
        self._minutes = value % 60

    @hours.setter
    def hours(self, value):
        self._hours = value % 24

    def tic(self):
        self.minutes += 1


c = Clock()

assert(c.minutes == 0 and c.hours == 0)

for i in range(24):
    assert(c.hours == i)
    for j in range(60):
        assert(c.hours == i and c.minutes == j)
        c.tic()
        print('{}:{}'.format(c.hours, c.minutes))

assert(c.minutes == 0 and c.hours == 0)

Excerpt and end of output:

12:57
12:58
12:59
13:0
13:1
13:2
13:3
.
.
.
23:46
23:47
23:48
23:49
23:50
23:51
23:52
23:53
23:54
23:55
23:56
23:57
23:58
23:59
0:0