Warning in g++ vs gcc

[Mathieu Malaterre]

Hello,

    I must be missing something really simple but how does one work 
around this :

$ cat demo.c
int main()
{
  int k = 375;
  double a = 3.75;
  k /= a;
  return 1;
}


$ g++ demo.c
demo.c: In function `int main()':
demo.c:5: warning: converting to `int' from `double'

whereas the gcc compilation does not raise anything.
Anyone to clear the distinction between gcc behavior and g++ ...
Or at least a way to get rid of this warning, I have trouble 
understanding why this code is considered dangerous.

Thanks,
Mathieu
Using: g++ --version 
               g++ (GCC) 3.3.5 (Debian 1:3.3.5-13)

Can reproduce with g++-4.0 (GCC) 4.0.1 and g++ (GCC) 4.1.0 20050719