/in/foo.cc: In function 'int main()':
/in/foo.cc:8:6: warning: variable 'a' set but not used [-Wunused-but-set-variable]
  int a[n],k,out[n];
      ^
/in/foo.cc:8:11: warning: unused variable 'k' [-Wunused-variable]
  int a[n],k,out[n];
           ^
/in/foo.cc:8:13: warning: unused variable 'out' [-Wunused-variable]
  int a[n],k,out[n];
             ^~~
/in/foo.cc:23:8: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<ans<<endl;
        ^~~