1 #include <stdexcept> 2 #include <iostream> 3 #include <array> 4 5 #include <boost/safe_numerics/safe_integer_range.hpp> 6 detected_msg(bool detected)7void detected_msg(bool detected){ 8 std::cout << (detected ? "error detected!" : "error NOT detected! ") << std::endl; 9 } 10 main(int,const char * [])11int main(int, const char *[]){ 12 // problem: array index values can exceed array bounds 13 std::cout << "example 5: "; 14 std::cout << "array index values can exceed array bounds" << std::endl; 15 std::cout << "Not using safe numerics" << std::endl; 16 std::array<int, 37> i_array; 17 18 // unsigned int i_index = 43; 19 // the following corrupts memory. 20 // This may or may not be detected at run time. 21 // i_array[i_index] = 84; // comment this out so it can be tested! 22 std::cout << "error NOT detected!" << std::endl; 23 24 // solution: replace unsigned array index with safe_unsigned_range 25 std::cout << "Using safe numerics" << std::endl; 26 try{ 27 using namespace boost::safe_numerics; 28 using i_index_t = safe_unsigned_range<0, i_array.size() - 1>; 29 i_index_t i_index; 30 i_index = 36; // this works fine 31 i_array[i_index] = 84; 32 i_index = 43; // throw exception here! 33 std::cout << "error NOT detected!" << std::endl; // so we never arrive here 34 } 35 catch(const std::exception & e){ 36 std::cout << "error detected:" << e.what() << std::endl; 37 } 38 return 0; 39 } 40