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- // Copyright (c) 2018Robert 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(){
- std::cout << "example 4: ";
- std::cout << "implicit conversions change data values" << std::endl;
- std::cout << "Not using safe numerics" << std::endl;
-
- // problem: implicit conversions change data values
- try{
- signed int a{-1};
- unsigned int b{1};
- std::cout << "a is " << a << " b is " << b << '\n';
- if(a < b){
- std::cout << "a is less than b\n";
- }
- else{
- std::cout << "b is less than a\n";
- }
- std::cout << "error NOT detected!" << std::endl;
- }
- catch(const std::exception &){
- // never arrive here - just produce the wrong answer!
- std::cout << "error detected!" << std::endl;
- return 1;
- }
- // solution: replace int with safe<int> and unsigned int with safe<unsigned int>
- std::cout << "Using safe numerics" << std::endl;
- try{
- using namespace boost::safe_numerics;
- safe<signed int> a{-1};
- safe<unsigned int> b{1};
- std::cout << "a is " << a << " b is " << b << '\n';
- if(a < b){
- std::cout << "a is less than b\n";
- }
- else{
- std::cout << "b is less than a\n";
- }
- std::cout << "error NOT detected!" << std::endl;
- return 1;
- }
- catch(const std::exception & e){
- // never arrive here - just produce the correct answer!
- std::cout << e.what() << std::endl;
- std::cout << "error detected!" << std::endl;
- }
- return 0;
- }
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