使用boost::u cast捕获溢出

你可以用一点精神来写你想写的东西:

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#include <boost/spirit/include/qi.hpp>
#include <iostream>

template <typename Out, typename In> Out numeric_lexical_cast(In const& range) {

    Out value;

    {
        using namespace boost::spirit::qi;
        using std::begin;
        using std::end;

        if (!parse(begin(range), end(range), auto_ >> eoi, value)) {
            struct bad_numeric_lexical_cast : std::domain_error {
                bad_numeric_lexical_cast() : std::domain_error("bad_numeric_lexical_cast") {}
            };
            throw bad_numeric_lexical_cast();
        }
    }

    return value;
}

int main()
{
    for (std::string const& input : { "23", "-23" }) try {
        std::cout << " == input: " << input << " -> ";
        auto i = numeric_lexical_cast<unsigned int>(input);
        std::cout << i << std::endl;
    } catch (std::exception const& e) {
        std::cout << e.what() << std::endl;
    }
}

印刷品

 == input: 23 -> 23
 == input: -23 -> bad_numeric_lexical_cast