/in/foo.cc: In function 'int main()':
/in/foo.cc:14:8: warning: statement has no effect [-Wunused-value]
   for(o;o<i;o++)
        ^
/in/foo.cc:19:8: warning: statement has no effect [-Wunused-value]
   for(q;q<n-i;q++)
        ^
/in/foo.cc:11:12: warning: 'p' may be used uninitialized in this function [-Wmaybe-uninitialized]
  while(p==0&&r==0)
        ~~~~^~~~~~
/in/foo.cc:11:12: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]