1 2 // Copyright (C) 2008-2018 Lorenzo Caminiti 3 // Distributed under the Boost Software License, Version 1.0 (see accompanying 4 // file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt). 5 // See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html 6 7 #include <limits> 8 #include <cassert> 9 10 //[introduction 11 #include <boost/contract.hpp> 12 inc(int & x)13void inc(int& x) { 14 boost::contract::old_ptr<int> old_x = BOOST_CONTRACT_OLDOF(x); // Old value. 15 boost::contract::check c = boost::contract::function() 16 .precondition([&] { 17 BOOST_CONTRACT_ASSERT(x < std::numeric_limits<int>::max()); // Line 17. 18 }) 19 .postcondition([&] { 20 BOOST_CONTRACT_ASSERT(x == *old_x + 1); // Line 20. 21 }) 22 ; 23 24 ++x; // Function body. 25 } 26 //] 27 main()28int main() { 29 int x = 10; 30 inc(x); 31 assert(x == 11); 32 return 0; 33 } 34 35