what's wrong with this helloworld program?

[ben]

When I try to gcc the following Helloworld program:

#include <iostream>

int main()
{
using namespace std;
cout << "Hello, World!!\n";
return 0;
}

I got errors as follows:

C:\Documents and Settings\benben>gcc ben.cpp
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x33):ben.cpp: undefined
refer
ence to `std::cout'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x38):ben.cpp: undefined
refer
ence to `std::basic_ostream<char, std::char_traits<char> >& std:perator<<
<std
::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&,
char c
onst*)'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x64):ben.cpp: undefined
refer
ence to `std::ios_base::Init::Init()'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x83):ben.cpp: undefined
refer
ence to `std::ios_base::Init::~Init()'

What has happend? Could anyone help me?

 

[Alvin]

When I try to gcc the following Helloworld program:

#include <iostream>

int main()
{
using namespace std;
cout << "Hello, World!!\n";
return 0;
}

I got errors as follows:
snip

What has happend? Could anyone help me?

You declare "using namespace std;" inside of main()...it should be outside.

 

[Tim Love]

When I try to gcc

Try g++
?

 

[Rolf Magnus]

When I try to gcc the following Helloworld program:

#include <iostream>

int main()
{
using namespace std;
cout << "Hello, World!!\n";
return 0;
}

I got errors as follows:

C:\Documents and Settings\benben>gcc ben.cpp
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x33):ben.cpp: undefined
refer
ence to `std::cout'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x38):ben.cpp: undefined
refer
ence to `std::basic_ostream<char, std::char_traits<char> >&
std:perator<< <std
::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&,
char c
onst*)'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x64):ben.cpp: undefined
refer
ence to `std::ios_base::Init::Init()'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x83):ben.cpp: undefined
refer
ence to `std::ios_base::Init::~Init()'

What has happend?

You used the compiler the wrong way.

Could anyone help me?

Try with g++ instead of gcc.

 

[Kai-Uwe Bux]

When I try to gcc the following Helloworld program:

#include <iostream>

int main()
{
using namespace std;
cout << "Hello, World!!\n";
return 0;
}

Nothing is wrong with the program.

I got errors as follows:

C:\Documents and Settings\benben>gcc ben.cpp
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x33):ben.cpp: undefined
refer
ence to `std::cout'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x38):ben.cpp: undefined
refer
ence to `std::basic_ostream<char, std::char_traits<char> >&
std:perator<< <std
::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&,
char c
onst*)'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x64):ben.cpp: undefined
refer
ence to `std::ios_base::Init::Init()'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x83):ben.cpp: undefined
refer
ence to `std::ios_base::Init::~Init()'

What has happend? Could anyone help me?

Try compiling with g++ instead of gcc.


Best

Kai-Uwe Bux

 

[ben]

That works! So is g++ specified for C++ programs and gcc for C programs?

ben

 

[ben]

Thanks a lot!

ben

Basically, yes. For the compiler, it doesn't matter much. g++ will assume
your code is C++, while gcc tries to detect it from the file name. However,
for linking, the difference is more important. For C++, the linker needs
some additional options (e.g. to link in the C++ standard library), and g++
adds those options, gcc doesn't.
Further questions about g++ should be asked in gnu.g++.help

 

[ben]

I think the using namespace statement is meant to be inside a function, for
localization's sake.

 

[Rolf Magnus]

That works! So is g++ specified for C++ programs and gcc for C programs?

Basically, yes. For the compiler, it doesn't matter much. g++ will assume
your code is C++, while gcc tries to detect it from the file name. However,
for linking, the difference is more important. For C++, the linker needs
some additional options (e.g. to link in the C++ standard library), and g++
adds those options, gcc doesn't.
Further questions about g++ should be asked in gnu.g++.help

 

[Ron Natalie]

That works! So is g++ specified for C++ programs and gcc for C programs?

In general, yes. The programs "g++" and "gcc" both invoke the same
compiler back ends, and either will compile .cpp or .c to .o as
as appropriate (some others as well). The difference is that g++
will seed the linker with the names of the C++ libraries, etc.. where
gcc assumes you're doing only C things.

 

[Richard Herring]

When I try to gcc the following Helloworld program:

#include <iostream>

int main()
{
using namespace std;
cout << "Hello, World!!\n";
return 0;
}

I got errors as follows:

C:\Documents and Settings\benben>gcc ben.cpp
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x33):ben.cpp: undefined
refer
ence to `std::cout'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x38):ben.cpp: undefined
refer
ence to `std::basic_ostream<char, std::char_traits<char> >& std:perator<<
<std
::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&,
char c
onst*)'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x64):ben.cpp: undefined
refer
ence to `std::ios_base::Init::Init()'
C:\DOCUME~1\benben\LOCALS~1\Temp/ccojbaaa.o(.text+0x83):ben.cpp: undefined
refer
ence to `std::ios_base::Init::~Init()'

What has happend?

Those are linker errors. You haven't included the correct libraries,
probably because you started the compiler in "C" mode instead of "C++"
mode.

Could anyone help me?

Try typing g++ instead of gcc ;-)

 

[Rolf Magnus]

In general, yes. The programs "g++" and "gcc" both invoke the same
compiler back ends, and either will compile .cpp or .c to .o as
as appropriate (some others as well).

Wrong (if by "appropriate" you mean that files with names ending in .c
should be compiled as C code). Consider this:

$ cat test.c
#include <stdlib.h>

int main()
{
int* x = malloc(sizeof(int));
free(x);
return 0;
}
$ gcc test.c
$ g++ test.c
test.c: In function `int main()':
test.c:5: error: invalid conversion from `void*' to `int*'

 

[Gianni Mariani]

When I try to gcc the following Helloworld program:

#include <iostream>

int main()
{
using namespace std;
cout << "Hello, World!!\n";
return 0;
}

As everyone else has pointed out - use g++ - however there might be an
error in your code.

std::basic_ostream (IIRC) is supposed to be defined in ostream, which
you do not include, hence it may not work on all compilers.

see:
http://groups-beta.google.com/group/comp.std.c++/msg/6f6abf4bc98c3d20?output=gplain

 

[Ioannis Vranos]

You declare "using namespace std;" inside of main()...it should be outside.

Actually what ben does is better.

 

[ben]

In The C++ Programming Language (Special Edition) by Bjarne Stroustrup,
page46, is Bjarne's Hello, world! version. He didn't include <ostream>
either.

ben

As everyone else has pointed out - use g++ - however there might be an
error in your code.

std::basic_ostream (IIRC) is supposed to be defined in ostream, which
you do not include, hence it may not work on all compilers.

see:

http://groups-beta.google.com/group/comp.std.c++/msg/6f6abf4bc98c3d20?output
=gplain

 

[Alf P. Steinbach]

* ben:

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