C++<iostream.h> 错误

Question

I am at the absolutely newest level of new when it comes to C++. It may seem like a noob mistake, but I think I'm missing something with my first program, "Hello World!".

I'm running from Ubuntu (not sure if this is any different from working with Windows), and I'm using a book called Teach Yourself C++ in 21 Days .

The code I'm resembling looks exactly like this:

#include <iostream.h>
int main()
{
cout <<"Hello World!\n";
    return 0;
}

I have this exactly in my text editor, but I keep getting greeted by the same error whenever I try to compile it!

first.cpp:2:22: fatal error: iostream.h: No such file or directory compilation terminated.

I'm pretty distressed as this is literally the first step in my coding career! I'm not sure if ubuntu needs to be treated differently than Windows (which is what the book is using as reference).

Help!

Answer 1

There are two problems here:

You need to omit the .h suffix:

#include <iostream>

Also, cout is an unqualified name, and needs to be qualified with the std namespace since you are not using namespace std :

std::cout << "Hello World!\n";

Answer 2

There shouldn't be any iostream.h it's simply called iostream and should look like this:

#include <iostream>
int main()
{
std::cout <<"Hello World!\n";
    return 0;
}

(also notice the std:: before the cout, since it means that it's from the standard namespace.)

Answer 3

You want just iostream

#include <iostream>

I suspect the book is very old. Names are qualified in the std namespace, so you may want to add

using namespace std;

For now at least.

Answer 4

use

#include <iostream>

in general STL header file don't have a .h

Answer 5

you need to compile using g++ compiler, not by gcc

g++ hello.cpp