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33 lines
859 B
C++
33 lines
859 B
C++
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// Copyright (C) 2008-2016 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_sqrt
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#include <boost/contract.hpp>
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#include <cmath>
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#include <cassert>
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double mysqrt(double x, double precision = 1e-6) {
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double result;
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boost::contract::guard c = boost::contract::function()
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.precondition([&] {
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BOOST_CONTRACT_ASSERT(x >= 0.0);
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})
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.postcondition([&] {
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BOOST_CONTRACT_ASSERT(fabs(result * result - x) <= precision);
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})
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;
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return result = sqrt(x);
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}
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int main() {
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double const precision = 1e-6;
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assert(fabs(mysqrt(4.0, precision) - 2.0) <= precision);
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return 0;
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}
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//]
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