Python学习 面向对象编程

这里自行定义了一个MyTime的类，继承于系统类object。在Python里面默认的情况的下都要继承于这个类。类里面对__init__,__str__，__add__，__iadd__函数进行了重载。其实严格上讲不能叫重载，因为Python不支持重载，确切说应该叫覆盖。里面我还企图对__init__进行再次重载，显然不允许的，放在那边做个比较。

#!/usr/bin/env python
class MyTime(object) :
'MyTime - operate hours, minutes and seconds'
def __init__(self, h, m, s) :
'MyTime - Constructor'
self.hour = h;
self.min = m;
self.sec = s;

#def __init__(self, seconds) :
#    'MyTime - Constructor'
#    self.hour = seconds / 3600
#    seconds = seconds % 3600
#    self.min = seconds /60
#    self.sec = seconds % 60

def __str__(self) :    #显示函数重载
'MyTime - string representation'
return '%d : %d : %d' % (self.hour, self.min, self.sec)
__repr__ = __str__
def __add__(self, time) :   #加法重载
'MyTime - overloading the addition operator'
h = m = s = 0
t = self.sec + time.sec
s = t % 60
m += t /60
t = self.min + time.min + m
m = t % 60
h = t / 60
t = self.hour + time.hour + h
h = t % 24
return self.__class__(h, m, s)

def __iadd__(self, time) :   #自增重载
'MyTime - overloading the in-place addition operator'
t = self.sec + time.sec
self.sec = t % 60
self.min += t / 60
t = self.min + time.min
self.min = t % 60
self.hour += t /60
t = self.hour + time.hour
self.hour = t % 24
return self
#测试部分
t1 = MyTime(12,34,57)
t2 = MyTime(8,6,56)
print 't1 >> ', t1
print 't2 >> ', t2
print 't1 + t2 >> ', t1 + t2
t1 += t2
print 't1 += t2 >> ', t1
#测试结果
#t1 >>  12 : 34 : 57
#t2 >>  8 : 6 : 56
#t1 + t2 >>  20 : 41 : 53
#t1 += t2 >>  20 : 41 : 53