Don't know if it's just a miscopy to the post but using g++:After fixing them it runs ok.Code:// In main.cpp usingnamespacestd; //gets error - in that cout and endl are not found. return0; // gets error - undifined variable. // not checking argc just gets "unused parameter" warning. // In stringLen.h #include stringLen.h // will include itself ad infinitum at compile time // because of "stupid" compiler:)