/in/foo.cc: In function 'int main()':
/in/foo.cc:4:19: warning: variable 'jia' set but not used [-Wunused-but-set-variable]
  int num,arr[101],jia,bejia,he,max=0,sum=0;
                   ^~~
/in/foo.cc:4:23: warning: unused variable 'bejia' [-Wunused-variable]
  int num,arr[101],jia,bejia,he,max=0,sum=0;
                       ^~~~~
/in/foo.cc:4:29: warning: unused variable 'he' [-Wunused-variable]
  int num,arr[101],jia,bejia,he,max=0,sum=0;
                             ^~