/in/foo.c: In function 'main':
/in/foo.c:34:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(i=0; i<N; i++)
  ^~~
/in/foo.c:37:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   sort(a);//一改错
   ^~~~