58 lines
1.7 KiB
C++
58 lines
1.7 KiB
C++
// Copyright (c) 2018Robert Ramey
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include <iostream>
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#include <boost/safe_numerics/safe_integer.hpp>
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int main(){
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std::cout << "example 4: ";
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std::cout << "implicit conversions change data values" << std::endl;
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std::cout << "Not using safe numerics" << std::endl;
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// problem: implicit conversions change data values
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try{
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signed int a{-1};
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unsigned int b{1};
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std::cout << "a is " << a << " b is " << b << '\n';
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if(a < b){
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std::cout << "a is less than b\n";
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}
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else{
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std::cout << "b is less than a\n";
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}
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std::cout << "error NOT detected!" << std::endl;
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}
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catch(const std::exception &){
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// never arrive here - just produce the wrong answer!
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std::cout << "error detected!" << std::endl;
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return 1;
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}
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// solution: replace int with safe<int> and unsigned int with safe<unsigned int>
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std::cout << "Using safe numerics" << std::endl;
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try{
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using namespace boost::safe_numerics;
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safe<signed int> a{-1};
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safe<unsigned int> b{1};
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std::cout << "a is " << a << " b is " << b << '\n';
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if(a < b){
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std::cout << "a is less than b\n";
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}
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else{
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std::cout << "b is less than a\n";
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}
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std::cout << "error NOT detected!" << std::endl;
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return 1;
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}
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catch(const std::exception & e){
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// never arrive here - just produce the correct answer!
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std::cout << e.what() << std::endl;
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std::cout << "error detected!" << std::endl;
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}
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return 0;
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}
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