C++ Compiling Problems

[Ian Malone]

Matthew Miller wrote:

 > Coert Waagmeester wrote:

 > in fact all of this ...
 >> I have an eBook from SAMS Teach yourself C++ in 21 days
 >> When I compiled their Hello World example:
 >>
 >> 1: #include <iostream.h>
 >> 2:
 >> 3: int main()
 >> 4: {
 >> 5:    cout << "Hello World!\n";
 >> 6:        return 0;
 >> 7: }
 >>
 >> g++ came back with:
 >> In file included from 
/usr/lib/gcc/i386-redhat-linux/3.4.2/../../../../include/c++/3.4.2/backward/iostream.h:31,from 
hello.cpp:1:
 >> 
/usr/lib/gcc/i386-redhat-linux/3.4.2/../../../../include/c++/3.4.2/backward/backward_warning.h:32:2: 
warning:
 >> #warning Thisfile includes at least one deprecated or antiquated
 >> header. Please consider using one of the 32 headers
 >> found in section 17.4.1.2 of the C++ standard. Examples include
 >> substituting the <X> header for the <X.h> header for C++ includes,
 >> or <iostream> instead of the deprecated header <iostream.h>. To
 >> disable this warning use -Wno-deprecated.


 > ... is *exactly* that issue -- iostream.h is the older, more-C-like
 > header file, and instead, you want the one called just iostream, with 
 > no extension.

The OP will probably be interested to know also that the example as
written won't compile if you simply substitute <iostream> for
<iostream.h>, for the same (Object orientated) reason.  In <iostream>
'cout' etc. live under the std namespace, so either 'cout' becomes
'std::cout' or you first expose cout using:
#include <iostream>
using std::cout;

Or expose the entire std namespace:
#include <iostream>
using namespace std;
(This one is useful because lots of the standard C++ functions and
classes like string live under std::)

-- 
imalone