109 lines
3.1 KiB
C++
109 lines
3.1 KiB
C++
// rational number example program ----------------------------------------//
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// (C) Copyright Paul Moore 1999. Permission to copy, use, modify, sell
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// and distribute this software is granted provided this copyright notice
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// appears in all copies. This software is provided "as is" without express or
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// implied warranty, and with no claim as to its suitability for any purpose.
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// boostinspect:nolicense (don't complain about the lack of a Boost license)
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// (Paul Moore hasn't been in contact for years, so there's no way to change the
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// license.)
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// Revision History
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// 14 Dec 99 Initial version
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#include <iostream>
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#include <cassert>
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#include <cstdlib>
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#include <boost/config.hpp>
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#ifndef BOOST_NO_LIMITS
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#include <limits>
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#else
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#include <limits.h>
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#endif
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#include <exception>
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#include <boost/rational.hpp>
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using std::cout;
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using std::endl;
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using boost::rational;
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#ifdef BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP
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// This is a nasty hack, required because MSVC does not implement "Koenig
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// Lookup". Basically, if I call abs(r), the C++ standard says that the
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// compiler should look for a definition of abs in the namespace which
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// contains r's class (in this case boost) - among other places.
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// Koenig Lookup is a relatively recent feature, and other compilers may not
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// implement it yet. If so, try including this line.
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using boost::abs;
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#endif
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int main ()
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{
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rational<int> half(1,2);
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rational<int> one(1);
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rational<int> two(2);
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// Some basic checks
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assert(half.numerator() == 1);
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assert(half.denominator() == 2);
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assert(boost::rational_cast<double>(half) == 0.5);
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// Arithmetic
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assert(half + half == one);
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assert(one - half == half);
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assert(two * half == one);
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assert(one / half == two);
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// With conversions to integer
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assert(half+half == 1);
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assert(2 * half == one);
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assert(2 * half == 1);
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assert(one / half == 2);
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assert(1 / half == 2);
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// Sign handling
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rational<int> minus_half(-1,2);
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assert(-half == minus_half);
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assert(abs(minus_half) == half);
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// Do we avoid overflow?
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#ifndef BOOST_NO_LIMITS
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int maxint = (std::numeric_limits<int>::max)();
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#else
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int maxint = INT_MAX;
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#endif
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rational<int> big(maxint, 2);
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assert(2 * big == maxint);
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// Print some of the above results
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cout << half << "+" << half << "=" << one << endl;
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cout << one << "-" << half << "=" << half << endl;
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cout << two << "*" << half << "=" << one << endl;
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cout << one << "/" << half << "=" << two << endl;
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cout << "abs(" << minus_half << ")=" << half << endl;
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cout << "2 * " << big << "=" << maxint
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<< " (rational: " << rational<int>(maxint) << ")" << endl;
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// Some extras
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rational<int> pi(22,7);
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cout << "pi = " << boost::rational_cast<double>(pi) << " (nearly)" << endl;
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// Exception handling
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try {
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rational<int> r; // Forgot to initialise - set to 0
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r = 1/r; // Boom!
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}
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catch (const boost::bad_rational &e) {
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cout << "Bad rational, as expected: " << e.what() << endl;
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}
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catch (...) {
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cout << "Wrong exception raised!" << endl;
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}
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return 0;
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}
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