/in/foo.cc: In function 'int main()':
/in/foo.cc:25:8: warning: variable 't' set but not used [-Wunused-but-set-variable]
    int t;
        ^
/in/foo.cc:29:6: error: redeclaration of 'int maxnum'
  int maxnum = 0;
      ^~~~~~
/in/foo.cc:6:36: note: 'int maxnum' previously declared here
  int n,a[max],num[max],sum,top,ave,maxnum;
                                    ^~~~~~
/in/foo.cc:32:8: error: 'i' was not declared in this scope
   for (i=1;i<=n;i++)
        ^