1 #include <stdexcept> 2 #include <iostream> 3 4 #include <boost/safe_numerics/safe_integer.hpp> 5 main(int,const char * [])6int main(int, const char *[]){ 7 // problem: cannot recover from arithmetic errors 8 std::cout << "example 8: "; 9 std::cout << "cannot detect compile time arithmetic errors" << std::endl; 10 std::cout << "Not using safe numerics" << std::endl; 11 12 try{ 13 const int x = 1; 14 const int y = 0; 15 // will emit warning at compile time 16 // will leave an invalid result at runtime. 17 std::cout << x / y; // will display "0"! 18 std::cout << "error NOT detected!" << std::endl; 19 } 20 catch(const std::exception &){ 21 std::cout << "error detected!" << std::endl; 22 } 23 // solution: replace int with safe<int> 24 std::cout << "Using safe numerics" << std::endl; 25 try{ 26 using namespace boost::safe_numerics; 27 const safe<int> x = 1; 28 const safe<int> y = 0; 29 // constexpr const safe<int> z = x / y; // note constexpr here! 30 std::cout << x / y; // error would be detected at runtime 31 std::cout << " error NOT detected!" << std::endl; 32 } 33 catch(const std::exception & e){ 34 std::cout << "error detected:" << e.what() << std::endl; 35 } 36 return 0; 37 } 38