/in/foo.cc: In function 'void bfs(int)':
/in/foo.cc:44:17: warning: unused variable 'ss' [-Wunused-variable]
  int nx,ny,step,ss;
                 ^~
/in/foo.cc: In function 'int main()':
/in/foo.cc:76:9: warning: unused variable 'x' [-Wunused-variable]
     int x;
         ^
/in/foo.cc: In function 'int dri(char)':
/in/foo.cc:26:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^