/in/foo.cc: In function 'bign& operator++(bign&, int)':
/in/foo.cc:278:10: warning: reference to local variable 't' returned [-Wreturn-local-addr]
     bign t=a;
          ^
/in/foo.cc: In function 'bign& operator--(bign&, int)':
/in/foo.cc:289:10: warning: reference to local variable 't' returned [-Wreturn-local-addr]
     bign t=a;
          ^