/in/foo.cc: In function 'void work()':
/in/foo.cc:92:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
   if(!out[i])
     ^
/in/foo.cc:102:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<scc[pos].size();i++)
              ~^~~~~~~~~~~~~~~~