Why can't g++ find iostream.h?
c++, g++
Solution
Before the C++ language was standardized by the ISO, the header file was named `<iostream.h>`, but when the C++98 standard was released, it was renamed to just `<iostream>` (without the `.h`). Change the code to use `#include <iostream>` instead and it should compile.
You'll also need to add a `using namespace std;` statement to each source file (or prefix each reference to an iostream function/object with a `std::` specifier), since namespaces did not exist in the pre-standardized C++. C++98 put the standard library functions and objects inside the `std` namespace.
Problem
I'm trying to understand how to compile C++ programs from the command line using g++ and (eventually) Clang on Ubuntu. I found a webpage which explains MakeFiles and I am following their directions. http://mrbook.org/tutorials/make/ I downloaded the four example files into their own directory. - main.cpp - hello.cpp - factorial.cpp - functions.h I then went ahead and ran their example of how to manually compile without a MakeFile. ``` g++ main.cpp hello.cpp factorial.cpp -o hello ``` When I ran the command from above, I received the following error from g++: ``` main.cpp:1:22: fatal error: iostream.h: No such file or directory compilation terminated. hello.cpp:1:22: fatal error: iostream.h: No such file or directory compilation terminated. ``` My only experience with writing c++ is using an IDE such as VS C++ Express or CodeBlocks. Isn't the compiler supposed to know what iostream.h is and where to find it? How do I get rid of this error so the program willl compile? Thanks for any help.