/in/foo.cc:18:15: error: redeclaration of 'int cp::cla1'
  int cla1,cla1,num;
               ^
/in/foo.cc:18:6: note: previous declaration 'int cp::cla1'
  int cla1,cla1,num;
      ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:28:33: error: 'struct cp' has no member named 'cla2'; did you mean 'cla1'?
   scanf("%d%d",&e[i].cla1,&e[i].cla2);
                                 ^~~~