Thank you for your quick replies, and apologies for asking what are probably quite simple questions. However I find the documentation of Lambda a bit confusing. Another sample I am having problems with: #include #include #include #include <vector> #include <string> #include <iostream> using boost::lambda::_1; class A { std::string s; public: A(std::string sIn):s(sIn){} void print_A() { std::cout<<"A="<5; } }; int main() { std::string in; std::vector alist; std::vector longAList; while(in!="end") { in=""; std::getline(std::cin,in); alist.push_back(new A(in)); } std::for_each(alist.begin(),alist.end(), boost::lambda::if_then(bind(&A::isLong,_1),longAList.push_back(_1))); return 1; } -------------------------------------- main.cpp: In function `int main()': main.cpp:37: error: no matching function for call to `std::vector >::push_back(const boost::lambda::lambda_functor >&)' Suggestions? Thanks -- Thad