c++ - boost 正则表达式错误:未初始化的 boost::match_results

Question

运行时

    bool my_compare(const std::string& string_1, const std::string& string_2)
    {
        const boost::regex str_re("so(m)e_(r)e(g)ex");
        boost::smatch str_match;     

        size_t one;
        uint8_t two;
        size_t three;
        if( boost::regex_search(string_1, str_match, str_re) ) {
            one = boost::lexical_cast<size_t>( std::string(str_match[1].first, match[1].second) );
            two = boost::lexical_cast<uint8_t>( std::string(str_match[2].first, match[2].second) );
            three = boost::lexical_cast<size_t>( std::string(str_match[3].first, match[3].second) );
        }
        size_t four;
        uint8_t five;
        size_t six;
        if( boost::regex_search(string_1, str_match, str_re) ) {
            four = boost::lexical_cast<size_t>( std::string(str_match[1].first, match[1].second) );
            five = boost::lexical_cast<uint8_t>( std::string(str_match[2].first, match[2].second) );
            six = boost::lexical_cast<size_t>( std::string(str_match[3].first, match[3].second) );
        }
        return false;
    }

    int main()
    {
       my_compare(some_string1, some_string2);
       return 0;
    }

我收到以下错误，我不明白:

terminate called after throwing an instance of 'boost::exception_detail::clone_impl

' what(): bad lexical cast: source type value could not be interpreted as target

Answer 1

"so(m)e_(r)e(g)ex"

此正则表达式将使用字符串 "m" 填充捕获 str_match[1]，使用字符串 填充 str_match[2] "r" 和 str_match[3] 与字符串 "g"

 boost::lexical_cast<size_t>( std::string(str_match[1].first, match[1].second) );

这将尝试将字符串 "m" 转换为 size_t 类型的值，但失败("m"不是整数!)，并抛出异常

' what(): bad lexical cast: source type value could not be interpreted as target

(顺便说一句，你不需要用一对迭代器中的字符串构造函数跳过这些步骤，子匹配可以直接转换为字符串)