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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
x + y;
}
catch(const std::exception & e){
// which can catch here
std::cout << e.what() << std::endl;
}
return 0;
}
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