/in/foo.c: In function 'main':
/in/foo.c:48:9: warning: too many arguments for format [-Wformat-extra-args]
  printf("Factors:", num);
         ^~~~~~~~~~
/in/foo.c:45:8: warning: 'num' is used uninitialized in this function [-Wuninitialized]
     sum=factor(m,fac, num);//一改错
     ~~~^~~~~~~~~~~~~~~~~~~