C++ question

ooagentbender · 11-19-2003, 02:19 PM

My c++ (what a joke) and now Im getting this retarded error I can't figure out.

any help would be appreciated. Ive tried everything including renaming the class and using namespace std and all that.

here are the file, it says Ive redeclared the class animal.

::UhUnix2:: gcc -c main.cpp
In file included from /usr/local/lib/gcc-lib/../../include/c++/3.3/backward/iostream.h:31,
/usr/local/lib/gcc-lib/../../include/c++/3.3/backward/backward_warning.h:32:2: warning: #warning This file 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 <sstream> instead of the deprecated header <strstream.h>. To disable this warning use -Wno-deprecated.
In file included from bird.h:2,
from main.cpp:3:
animal.h:2: error: redefinition of `class animal'
animal.h:2: error: previous definition of `class animal'
In file included from cow.h:1,
from main.cpp:4:
animal.h:2: error: redefinition of `class animal'
animal.h:2: error: previous definition of `class animal'
In file included from main.cpp:4:
cow.h:12:3: warning: no newline at end of file
main.cpp:27:2: warning: no newline at end of file
animal.h:8: warning: inline function `animal::~animal()' used but never defined
animal.h:8: warning: inline function `animal::~animal()' used but never defined
animal.h:7: warning: inline function `animal::animal()' used but never defined
animal.h:8: warning: inline function `animal::~animal()' used but never defined

http://www2.hawaii.edu/~benderj/cow.cpp
http://www2.hawaii.edu/~benderj/bird.cpp
http://www2.hawaii.edu/~benderj/animal.cpp
http://www2.hawaii.edu/~benderj/animal.h
http://www2.hawaii.edu/~benderj/bird.h
http://www2.hawaii.edu/~benderj/cow.h
http://www2.hawaii.edu/~benderj/main.cpp

acid_kewpie · 11-19-2003, 02:36 PM

well yes you ARE redefining variables, as you have two includes for the sames header. you need to use preprocessor checks:

Code:

#ifndef ANIMAL_H
include "animal.h"
#endif

#define ANIMAL_H

this ensures the header there is only included once. obviously once it is included it is available to the entire code...

Mara · 11-19-2003, 02:36 PM

Use g++ to compile the program. It should be better.
First note looking into the source code: when writing something.h file, do it the following way

Code:

#ifndef SOMETHING_H
#define SOMETHING_H

//your definitions here

#endif

The variable (SOMETHING_H) must be different in all files. Such a construction allows to load one header once only In your code, one header may be loaded multiple times, what causes a problem.
Not sure if it's all, but it should help.

ooagentbender · 11-19-2003, 03:02 PM

im a moron, seriously

acid_kewpie · 11-19-2003, 03:44 PM

Quote:

Originally posted by ooagentbender
im a moron, seriously

i'd like to say i know the feeling but....

oh...

yes i DO know the feeling.