folks I am almost completely new to programming so please bear with me. I am using the first example from lydia.com c++ videos and failing. I am using Xcode 4.5.1 with a c++ command line project instead of eclipse and I am getting an error on compile of iostream file not found. the code is simple and I will include exactly what I have at the end of this message. I thought that iostream was a standard header that came with all even remotely recent versions of c++ compilers and am shocked to get this error and I cannot find any way to fix this. please tell me whats going on. #include <iostream> #include <stdio.h> #include <sstream> #include <vector> int main(int argc, char ** argv) { stringstream version; version << "GCC Version"; _GNUC_<<"."<<_GNUC_MINOR_<<"."<<_GNUC_PATCHLEVEL_<<_"\nVersion String: " <<_VERSION_; cout <<version.string() endl; vector<string> v={"one","two","three"}; for ( s : v ) { cout << s <<endl; } // insert code here... printf("Hello, World!\n"); return 0; } Thanks.