Dear advanced g++ programers: I tried to copy/test a piece simple boost library's lexical_cast c++ code from book c++Cookbook, page 122, example 3-2. ---------------------------------------------------------- // Example 3-2. Using lexical_cast #include <iostream> #include <string> #include "boost/lexical_cast.hpp" /* I comple this program * right above directory boost */ // <boost/lexical_cast.hpp> using namespace std; int main() { string str1 = "750"; string str2 = "2.71"; string str3 = "0x7FFF"; try { cout << boost::lexical_cast<int>(str1) << endl; cout << boost::lexical_cast<double>(str2) << endl; cout << boost::lexical_cast<int>(str3) << endl; } catch (boost::bad_lexical_cast& e) { cerr << "Bad cast: " << e.what() << endl; } } ----------------------------------------------------- --------------- eric@eric-laptop:~/boost1/boost_1_46_1$ g++ usinglexicast.cpp usinglexicast.cpp: In function ‘int main()’: usinglexicast.cpp:16:34: error: ‘str3’ cannot appear in a constant-expression usinglexicast.cpp:16:21: error: no match for ‘operator<<’ in ‘std::cout << lexical_cast<<expression error> >’ /usr/local/lib/gcc/i686-pc-linux-gnu/4.5.2/../../../../include/c ++/4.5.2/ostream:108:7: note: candidates are: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__ostream_type& (*)(std::basic_ostream<_CharT, _Traits>::__ostream_type&)) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>] ------------------------------------------------------------ This is only beginning portion of more longer g++ compile errors. plz help thanks a lot in advance Eric