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- // Copyright (c) 2018 Robert Ramey
- //
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- #include <iostream>
- #include <boost/safe_numerics/safe_integer.hpp>
- int main(int, const char * []){
- std::cout << "example 1:";
- std::cout << "undetected erroneous expression evaluation" << std::endl;
- std::cout << "Not using safe numerics" << std::endl;
- // problem: arithmetic operations can yield incorrect results.
- try{
- std::int8_t x = 127;
- std::int8_t y = 2;
- std::int8_t z;
- // this produces an invalid result !
- z = x + y;
- std::cout << z << " != " << x + y << std::endl;
- std::cout << "error NOT detected!" << std::endl;
- }
- catch(const std::exception &){
- std::cout << "error detected!" << std::endl;
- }
- // solution: replace std::int8_t with safe<std::int8_t>
- std::cout << "Using safe numerics" << std::endl;
- try{
- using namespace boost::safe_numerics;
- safe<std::int8_t> x = 127;
- safe<std::int8_t> y = 2;
- // rather than producing and invalid result an exception is thrown
- safe<std::int8_t> z = x + y;
- }
- catch(const std::exception & e){
- // which can catch here
- std::cout << e.what() << std::endl;
- }
- return 0;
- }
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