Can't get 'Hello World' to compile

[Ken J]

Hi, I am a COMPLETE newby at programming but am trying hard to get as far as I can on my own. I have installed Cygwin, with the gcc compiler package, and it all seems to be working OK. I'm using the 'Hello World' sample program used in the tutorial here - code is as follows:

// my first program in C++

#include <iostream>
using namespace std;

int main ()
{
cout << "Hello World!";
return 0;
}

I have saved the text to file c:\cygwin\hello.c, then from within Cygwin I have typed:
gcc /hello.c -o hello.exe. I get the following error messages:

/hello.c:3:20 iostream: No such file or directory
/hello.c:4: error: parse error before "namespace"
/hello.c:4: warning: data definition has no type or storage class
/hello.c: In function 'main':
/hello.c:8: error: 'cout' undeclared (first use in this function)
/hello.c:8: error (Each undeclared identifier is reported only once
/hello.c:8: error for each function it appears in.)

After searching for some answers with Google, I found several others having similar problems. The suggested answers for them did not work for me. One suggested solution was that the iostream library was not installed. I installed the ENTIRE 800 mb Cygwin package, including all libraries. Another suggestion was that it was a pathing issue. I do think I have a pathing issue, or I wouldn't have to use the leading '/' before hello.c - i should be able to use:
gcc hello.c -o hello.exe. But I don't know what else to do about the pathing - I added C:\Cygwin, and C:\Cygwin\home\username\ to my set path environment variable and rebooted Win XP Pro SP3.

The reason I said Cygwin seems to be working OK is that this other program works correctly (taken from Cygwin's User's guide):

http://cygwin.com/cygwin-ug-net/setup-maxmem.html

main()
{
unsigned int bit=0x40000000, sum=0;
char *x;
while (bit > 4096)
{
x = malloc(bit);
if (x)
sum += bit;
bit >>= 1;
}
printf("%08x bytes (%.1fMb)\n", sum, sum/1024.0/1024.0);
return 0;
}

It both compiles and executes properly.

If someone could help straighten me out on this, I'd love to move past step one in learning how to program!

Thank you, Ken

[guestgulkan]

Ah, I do notice that you said you saved the file as c:\cygwin\hello.c.
As this is a C++ file you are trying to do - try saving it as c:\cygwin\hello.cpp.

It may not be the answer to all your problems - but it is certainly the answer to one of them.

[Ken J]

Thank you for the reply. I re-saved the file as c:\cygwin\hello.cpp and tried to compile it again. This time I got an entirely new set of errors (but none of the previous ones):

/cygdrive/c/DOCUME~1/username/LOCALS~1/Temp/ccxVOVgI.o:hello.cpp:(.text+0xd): undefined reference to 'std::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const'
/cygdrive/c/DOCUME~1/username/LOCALS~1/Temp/ccxVOVgI.o:hello.cpp:(.text+0x60): undefined reference to 'std::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const'
/cygdrive/c/DOCUME~1/username/LOCALS~1/Temp/ccxVOVgI.o:hello.cpp:(.text+0x9f): undefined reference to 'std::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const'
/cygdrive/c/DOCUME~1/username/LOCALS~1/Temp/ccxVOVgI.o:hello.cpp:(.text+0xce): undefined reference to 'std::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const'
/cygdrive/c/DOCUME~1/username/LOCALS~1/Temp/ccxVOVgI.o:hello.cpp:(.text+0x135): undefined reference to 'std::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const'
/cygdrive/c/DOCUME~1/username/LOCALS~1/Temp/ccxVOVgI.o:hello.cpp:(.text+0x13a): undefined reference to 'std::basic_ostream<char, std::char_traits<char>, std::operator<char> >::size() const'
/cygdrive/c/DOCUME~1/username/LOCALS~1/Temp/ccxVOVgI.o:hello.cpp:(.text+0x163): undefined reference to 'std::ios_base::Init::Init()'
/cygdrive/c/DOCUME~1/username/LOCALS~1/Temp/ccxVOVgI.o:hello.cpp:(.text+0x17e): undefined reference to 'std::ios_base::Init::Init()'
collect2: 1d returned 1 exit status

BTW the other program I referred to in the OP is saved as 'max_memory.c' and it compiles fine in Cygwin. No error messages at all and it produces 'max_memory.exe', which works when launched.

Thanks again, Ken

[Ken J]

OK, the problem was I was using the wrong compiler - I needed to use g++ instead of gcc AND change to file name to .cpp.

Yay, I'm out of the starting block!

Ken

[guestgulkan]

Damn, I didn't notice the GCC

[chrisname]

If you want to continue using GCC you need to add -lstdc++ when you compile.