1///////////////////////////////////////////////////////////////////////////////
2// Copyright 2015 John Maddock. Distributed under the Boost
3// Software License, Version 1.0. (See accompanying file
4// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5
6#include <boost/rational.hpp>
7
8
9int main()
10{
11#ifndef BOOST_NO_CXX11_CONSTEXPR
12 constexpr boost::rational<int> i1;
13 constexpr boost::rational<int> i2(3);
14 constexpr boost::rational<long long> i3(i2);
15 constexpr boost::rational<short> i4(i2);
16 constexpr boost::rational<long long> i5(23u); // converting constructor
17 // constexpr boost::rational<short> i6(23u); // Not supported, needs an explicit typecast in constructor.
18
19 static_assert(i1.numerator() == 0, "constexpr test");
20 static_assert(i1.denominator() == 1, "constexpr test");
21 static_assert(i2.numerator() == 3, "constexpr test");
22 static_assert(i2.denominator() == 1, "constexpr test");
23 static_assert(i3.numerator() == 3, "constexpr test");
24 static_assert(i3.denominator() == 1, "constexpr test");
25 static_assert(!i1, "constexpr test");
26 static_assert(i2, "constexpr test");
27#endif
28 return 0;
29}
30

source code of boost/libs/rational/test/constexpr_test.cpp