BOOST轉換lexical_cast

lexical_cast非常好用，基本用法就不介紹了，下面是一些奇門異術。

lexical_cast讀取16進制字符串，轉換成數值

template <typename T>
struct HexTo {
    T value;
    operator T() const {return value;}
    friend std::istream& operator>>(std::istream& in, HexTo& out) {
        in >> std::hex >> out.value;
        return in;
    }
};

int main(void) {
    int x = boost::lexical_cast<HexTo<int>>("1A"); 
}