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58 lines
1.4 KiB
C++
58 lines
1.4 KiB
C++
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//[n1962_circle
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#include <boost/contract.hpp>
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#include <boost/detail/lightweight_test.hpp>
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#include <cassert>
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class shape {
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public:
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virtual ~shape() {}
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virtual int compute_area(boost::contract::virtual_* v = 0) const = 0;
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};
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int shape::compute_area(boost::contract::virtual_* v) const {
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int result;
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auto c = boost::contract::public_function(v, result, this)
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.postcondition([&] (int const& result) {
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BOOST_CONTRACT_ASSERT(result > 0);
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})
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;
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assert(false); return result = -1; // Never gets here.
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}
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class circle
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#define BASES public shape
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: BASES
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{
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public:
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typedef BOOST_CONTRACT_BASE_TYPES(BASES) base_types;
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#undef BASES
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int radius; // Make sure to set this...
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static int const pi = 3; // Truncated to int from 3.14...
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virtual int compute_area(boost::contract::virtual_* v = 0)
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const /* override */ {
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int result;
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auto c = boost::contract::public_function<override_compute_area>(
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v, result, &circle::compute_area, this)
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.postcondition([&] (int const& result) {
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BOOST_CONTRACT_ASSERT(result == pi * radius * radius);
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})
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;
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return result = pi * radius * radius;
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}
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BOOST_CONTRACT_OVERRIDE(compute_area);
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};
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int main() {
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circle c;
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c.radius = 2;
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BOOST_TEST_EQ(c.compute_area(), 12);
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return boost::report_errors();
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}
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//]
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