/in/foo.cc: In function 'int main()':
/in/foo.cc:33:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int i=1;i<=n;i++)
  ^~~
/in/foo.cc:35:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   mergesort(a,1,n);
   ^~~~~~~~~