/in/foo.cc: In function 'int main()':
/in/foo.cc:6:2: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
  while(~scanf("%d",&a[++n]));
  ^~~~~
/in/foo.cc:7:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'while'
   n--;
   ^