/in/foo.c: In function 'main':
/in/foo.c:6:2: warning: 'n' is used uninitialized in this function [-Wuninitialized]
  for(int i=0;i<n;i++)
  ^~~
/in/foo.c:12:4: warning: 'k' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if(k==n-2&&n%2==0)
    ^