make sure you #include <assert.h>
I did include it. I didn't put my assert in the main though, it's under the length function, do you think that could be the problem?
This is what it says when I try to build:
"warning: control reaches end of non-void function" and it indicates the line where I put assert.
You forgot to return something from the function.
if your functions isn't void, you need to return a value;