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1 | ////////////////////////////////////////////////////////////////// | |
2 | // example94.cpp | |
3 | // | |
4 | // Copyright (c) 2015 Robert Ramey | |
5 | // | |
6 | // Distributed under the Boost Software License, Version 1.0. (See | |
7 | // accompanying file LICENSE_1_0.txt or copy at | |
8 | // http://www.boost.org/LICENSE_1_0.txt) | |
9 | ||
10 | // illustrate usage of safe<int> as drop-in replacement for int in | |
11 | // a more complex library. Use an example from the boost.rational | |
12 | // library with modifications to use safe<int> rather than int | |
13 | ||
14 | // rational number example program ----------------------------------------// | |
15 | ||
16 | // (C) Copyright Paul Moore 1999. Permission to copy, use, modify, sell | |
17 | // and distribute this software is granted provided this copyright notice | |
18 | // appears in all copies. This software is provided "as is" without express or | |
19 | // implied warranty, and with no claim as to its suitability for any purpose. | |
20 | ||
21 | // boostinspect:nolicense (don't complain about the lack of a Boost license) | |
22 | // (Paul Moore hasn't been in contact for years, so there's no way to change the | |
23 | // license.) | |
24 | ||
25 | // Revision History | |
26 | // 14 Dec 99 Initial version | |
27 | ||
28 | #include <iostream> | |
29 | #include <cassert> | |
30 | #include <cstdlib> | |
31 | #include <boost/config.hpp> | |
32 | #include <limits> | |
33 | #include <exception> | |
34 | #include <boost/rational.hpp> | |
35 | ||
36 | #include <boost/safe_numerics/safe_integer.hpp> | |
37 | ||
38 | using std::cout; | |
39 | using std::endl; | |
40 | using boost::rational; | |
41 | using namespace boost::safe_numerics; | |
42 | ||
43 | using int_type = safe<int>; | |
44 | ||
45 | int main () | |
46 | { | |
47 | rational<int_type> half(1,2); | |
48 | rational<int_type> one(1); | |
49 | rational<int_type> two(2); | |
50 | ||
51 | // Some basic checks | |
52 | assert(half.numerator() == 1); | |
53 | assert(half.denominator() == 2); | |
54 | // assert(boost::rational_cast<double>(half) == 0.5); | |
55 | ||
56 | static_assert( | |
57 | ! boost::safe_numerics::is_safe<rational<int_type>>::value, | |
58 | "rational<int_type> is safe" | |
59 | ); | |
60 | ||
61 | // Arithmetic | |
62 | assert(half + half == one); | |
63 | assert(one - half == half); | |
64 | assert(two * half == one); | |
65 | assert(one / half == two); | |
66 | ||
67 | // With conversions to integer | |
68 | assert(half+half == 1); | |
69 | assert(2 * half == one); | |
70 | assert(2 * half == 1); | |
71 | assert(one / half == 2); | |
72 | assert(1 / half == 2); | |
73 | ||
74 | // Sign handling | |
75 | rational<int_type> minus_half(-1,2); | |
76 | assert(-half == minus_half); | |
77 | assert(abs(minus_half) == half); | |
78 | ||
79 | // Do we avoid overflow? | |
80 | int maxint = (std::numeric_limits<int>::max)(); | |
81 | rational<int_type> big(maxint, 2); | |
82 | assert(2 * big == maxint); | |
83 | ||
84 | // Print some of the above results | |
85 | cout << half << "+" << half << "=" << one << endl; | |
86 | cout << one << "-" << half << "=" << half << endl; | |
87 | cout << two << "*" << half << "=" << one << endl; | |
88 | cout << one << "/" << half << "=" << two << endl; | |
89 | cout << "abs(" << minus_half << ")=" << half << endl; | |
90 | cout << "2 * " << big << "=" << maxint | |
91 | << " (rational: " << rational<int>(maxint) << ")" << endl; | |
92 | ||
93 | // Some extras | |
94 | // rational<int_type> pi(22,7); | |
95 | // cout << "pi = " << boost::rational_cast<double>(pi) << " (nearly)" << endl; | |
96 | ||
97 | // Exception handling | |
98 | try { | |
99 | rational<int_type> r; // Forgot to initialise - set to 0 | |
100 | r = 1/r; // Boom! | |
101 | } | |
102 | catch (const boost::bad_rational &e) { | |
103 | cout << "Bad rational, as expected: " << e.what() << endl; | |
104 | } | |
105 | catch (...) { | |
106 | cout << "Wrong exception raised!" << endl; | |
107 | } | |
108 | return 0; | |
109 | } |