/in/foo.cc: In function 'int main()':
/in/foo.cc:26:8: warning: unused variable 't' [-Wunused-variable]
    int t=a[i];a[i]=a[k];a[k]=i;
        ^
/in/foo.cc:30:6: error: 'k' was not declared in this scope
  for(k=1;k<=3;k++)
      ^
/in/foo.cc:32:8: error: 'i' was not declared in this scope
   for (i=1;i<=n;i++)
        ^
/in/foo.cc:6:36: warning: unused variable 'most' [-Wunused-variable]
  int n,a[max],num[max],sum,top,ave,most;
                                    ^~~~
/in/foo.cc:7:7: warning: unused variable 'ismost' [-Wunused-variable]
  bool ismost[max];
       ^~~~~~