OPPGAVE 4:
----------


    public int sum(BinNode t){
 
         if(t == null){
             return 0;
         }else{
             return t.data + sum(t.right) + sum(t.left);
         }
 
     }
 
 
     public int antall(BinNode t){
         if(t == null){
             return 0;
         }else{
             return 1 + antall(t.left) + antall(t.right);
         }
     }