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- // Copyright (C) 2008-2018 Lorenzo Caminiti
- // Distributed under the Boost Software License, Version 1.0 (see accompanying
- // file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
- // See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
- //[n1962_equal
- #include <boost/contract.hpp>
- #include <cassert>
- // Forward declaration because == and != contracts use one another's function.
- template<typename T>
- bool operator==(T const& left, T const& right);
- template<typename T>
- bool operator!=(T const& left, T const& right) {
- bool result;
- boost::contract::check c = boost::contract::function()
- .postcondition([&] {
- BOOST_CONTRACT_ASSERT(result == !(left == right));
- })
- ;
- return result = (left.value != right.value);
- }
- template<typename T>
- bool operator==(T const& left, T const& right) {
- bool result;
- boost::contract::check c = boost::contract::function()
- .postcondition([&] {
- BOOST_CONTRACT_ASSERT(result == !(left != right));
- })
- ;
- return result = (left.value == right.value);
- }
- struct number { int value; };
- int main() {
- number n;
- n.value = 123;
- assert((n == n) == true); // Explicitly call operator==.
- assert((n != n) == false); // Explicitly call operator!=.
- return 0;
- }
- //]
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