Mercurial > cpython-lru_cache-weakref

annotate Demo/classes/Rat.py @ 4566:6403c94de50d legacy-trunk

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Added safeguard against failure in __del__.
author Guido van Rossum <guido@python.org>
date Wed, 27 Nov 1996 19:39:58 +0000
parents dd7be8128410
children ba005e4db4c5
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
1 # Rational numbers
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
2
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
3 from types import *
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
4
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
5 def rat(num, den):
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
6 if type(num) == FloatType or type(den) == FloatType:
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
7 return num/den
1427
8701b93383ab *** empty log message ***
Guido van Rossum <guido@python.org>
parents: 1371
diff changeset
8 return Rat(num, den)
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
9
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
10
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
11 def gcd(a, b):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
12 while b:
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
13 a, b = b, a%b
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
14 return a
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
15
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
16
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
17 class Rat:
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
18
1427
8701b93383ab *** empty log message ***
Guido van Rossum <guido@python.org>
parents: 1371
diff changeset
19 def __init__(self, num, den):
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
20 if den == 0:
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
21 raise ZeroDivisionError, 'rat(x, 0)'
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
22 if type(den) == FloatType or type(num) == FloatType:
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
23 g = float(den)
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
24 else:
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
25 g = gcd(num, den)
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
26 self.num = num/g
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
27 self.den = den/g
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
28
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
29 def __repr__(self):
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
30 return 'Rat(%s, %s)' % (self.num, self.den)
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
31
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
32 def __str__(self):
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
33 if self.den == 1:
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
34 return str(self.num)
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
35 else:
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
36 return '%s/%s' % (self.num, self.den)
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
37
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
38 def __cmp__(a, b):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
39 c = a-b
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
40 if c.num < 0:
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
41 return -1
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
42 if c.num > 0:
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
43 return 1
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
44 return 0
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
45
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
46 def __float__(self):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
47 return float(self.num) / float(self.den)
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
48
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
49 def __long__(self):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
50 return long(self.num) / long(self.den)
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
51
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
52 def __int__(self):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
53 return int(self.num / self.den)
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
54
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
55 def __coerce__(a, b):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
56 t = type(b)
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
57 if t == IntType:
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
58 return a, Rat(b, 1)
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
59 if t == LongType:
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
60 return a, Rat(b, 1L)
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
61 if t == FloatType:
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
62 return a, Rat(b, 1.0)
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
63 if t == InstanceType and a.__class__ == b.__class__:
1427
8701b93383ab *** empty log message ***
Guido van Rossum <guido@python.org>
parents: 1371
diff changeset
64 return a, b
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
65 raise TypeError, 'Rat.__coerce__: bad other arg'
1427
8701b93383ab *** empty log message ***
Guido van Rossum <guido@python.org>
parents: 1371
diff changeset
66
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
67 def __add__(a, b):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
68 return rat(a.num*b.den + b.num*a.den, a.den*b.den)
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
69
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
70 def __sub__(a, b):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
71 return rat(a.num*b.den - b.num*a.den, a.den*b.den)
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
72
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
73 def __mul__(a, b):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
74 return rat(a.num*b.num, a.den*b.den)
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
75
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
76 def __div__(a, b):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
77 return rat(a.num*b.den, a.den*b.num)
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
78
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
79 def __neg__(self):
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
80 return rat(-self.num, self.den)
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
81
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
82
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
83 def test():
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
84 print Rat(-1L, 1)
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
85 print Rat(1, -1)
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
86 a = Rat(1, 10)
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
87 print int(a), long(a), float(a)
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
88 b = Rat(2, 5)
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
89 l = [a+b, a-b, a*b, a/b]
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
90 print l
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
91 l.sort()
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
92 print l
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
93 print Rat(0, 1)
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
94 print a+1
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
95 print a+1L
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
96 print a+1.0
1371
faaf3843b8bd Add coercions
Guido van Rossum <guido@python.org>
parents: 945
diff changeset
97 try:
1966
dd7be8128410 adapted to new overloading scheme
Guido van Rossum <guido@python.org>
parents: 1427
diff changeset
98 print Rat(1, 0)
1371
faaf3843b8bd Add coercions
Guido van Rossum <guido@python.org>
parents: 945
diff changeset
99 raise SystemError, 'should have been ZeroDivisionError'
faaf3843b8bd Add coercions
Guido van Rossum <guido@python.org>
parents: 945
diff changeset
100 except ZeroDivisionError:
faaf3843b8bd Add coercions
Guido van Rossum <guido@python.org>
parents: 945
diff changeset
101 print 'OK'
945
465b9841770e Initial revision
Guido van Rossum <guido@python.org>
parents:
diff changeset
102
1427
8701b93383ab *** empty log message ***
Guido van Rossum <guido@python.org>
parents: 1371
diff changeset
103 test()