/in/foo.cc: In function 'int main()':
/in/foo.cc:21:6: warning: 'n' may be used uninitialized in this function [-Wmaybe-uninitialized]
   x[n++]=jw;
     ~^~
/in/foo.cc:27:6: note: 'n' was declared here
  int n,x[N];
      ^