40 lines
1.0 KiB
C++
40 lines
1.0 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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#include <boost/contract.hpp>
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int gcd(int const a, int const b) {
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int result;
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boost::contract::check c = boost::contract::function()
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.precondition([&] {
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BOOST_CONTRACT_ASSERT(a > 0);
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BOOST_CONTRACT_ASSERT(b > 0);
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})
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.postcondition([&] {
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BOOST_CONTRACT_ASSERT(result <= a);
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BOOST_CONTRACT_ASSERT(result <= b);
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})
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;
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int x = a, y = b;
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while(x != y) {
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if(x > y) x = x - y;
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else y = y - x;
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}
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return result = x;
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}
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//[check_macro
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int main() {
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// Implementation checks (via macro, disable run-/compile-time overhead).
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BOOST_CONTRACT_CHECK(gcd(12, 28) == 4);
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BOOST_CONTRACT_CHECK(gcd(4, 14) == 2);
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return 0;
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}
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//]
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