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