/in/foo.cc: In function 'long long unsigned int fun(std::__cxx11::string)':
/in/foo.cc:7:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<str.length();i++){
               ^
/in/foo.cc:6:25: warning: variable 'a' set but not used [-Wunused-but-set-variable]
  unsigned long long int a[100]={0},sum=0;
                         ^