contract/example/features/lambda.cpp

44 lines
1.2 KiB
C++

// 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
#include <boost/contract.hpp>
#include <vector>
#include <algorithm>
#include <limits>
int main() {
std::vector<int> v;
v.push_back(1);
v.push_back(2);
v.push_back(3);
//[lambda
int total = 0;
std::for_each(v.cbegin(), v.cend(),
// Contract for a lambda function.
[&total] (int const x) {
boost::contract::old_ptr<int> old_total =
BOOST_CONTRACT_OLDOF(total);
boost::contract::check c = boost::contract::function()
.precondition([&] {
BOOST_CONTRACT_ASSERT(
total < std::numeric_limits<int>::max() - x);
})
.postcondition([&] {
BOOST_CONTRACT_ASSERT(total == *old_total + x);
})
;
total += x; // Lambda function body.
}
);
//]
assert(total == 6);
return 0;
}