Boost.LexicalCast provides a cast operator, boost::lexical_cast, that can covert numberes from strings to numeric types like int or double.

#include 
     
      #include 
      
       #include 
       
        int main() {  std::string s = boost::lexical_cast
        
         (123);  std::cout << s << std::endl;  double d = boost::lexical_cast
         
          (s);  std::cout << d << std::endl;  return 0;}
         
        
       
      
     

boost::lexical_cast uses streams internally to perform the conversion. Therefore, only types with overloader operator<< and operator>> can be converted.

If a conversion fails, an exception of type boost::bad_lexical_cast, which is derived from std::bad_cast, is thrown.