Yes. The glutinous rice wrapped in zongzi itself is raw and needs to be cooked at high temperature. Adding rock sugar can also melt at high temperature, which can make zongzi more sweet.

According to your own needs. You can put sugar or other sweet food when making zongzi, which depends on your own taste and the type of making zongzi. If you want to make sweet zongzi without adding other sweet fillings, you must put sugar in it so that you can make sweet zongzi.

If sweet fillings, such as candied fruit, red beans, red dates, etc., have been put into the dumplings, the sweetness of these foods is not low, so sugar is not needed. Secondly, sugar doesn't have to be put when wrapping zongzi, but it can also be made into original zongzi, and then eaten with white sugar, which is also a sweet zongzi.