/in/foo.cc: In function 'int main()':
/in/foo.cc:4:53: warning: unused variable 't' [-Wunused-variable]
  unsigned long long n,i,f,f1=1,f2=1,last=1,result=0,t=0;
                                                     ^
/in/foo.cc:16:8: warning: 'f' may be used uninitialized in this function [-Wmaybe-uninitialized]
  result=f/last;
  ~~~~~~^~~~~~~