does code::blocks reserve names other than c++ keywords?

does code::blocks reserve names other than c++ keywords?

I am new to code::blocks and quite unexperienced in c++ as well. I know
there are many keywords, that I am not supposed to use for variable names
and they are usually displayed in a different color, as they are in
visualstudio. Now when I was copying some code fragments over from my old
vs project to a new code::blocks project, some of my variable names
suddenly got colored. For example in this code the variables begin and end
are displayed in green now, and I don't understand why.
int begin = 0;
int end = 4;
int myarray[end];
for (int i = begin; i < end; i++)
{
myarray[i] = i;
}
In some cases, this code won't even compile and I get strange "conflicting
declaration" errors. May I use these names anyway, or are they somehow
reserved in code::blocks? I looked into some books, but as far as I know,
they are no c++ keywords. Is the reason, that I am using c++11 now? I am
using v.12.11 of the ide and the mingw compiler, that comes with it. Thank
you for your help.