Getting no output

please tell me where i am doing mistake, as i am not getting any output

First mistake is that here in this question you do not have to compare data.
You just have to compare the shape or the structure.
Also you were not handling the base case correctly. You did have a case when both the root reaches NULL, because of which there was a segmentation fault

Check now

you use graphs data structures which we were not taught till yet. Can you correct my code i am continuously getting error

oh sorry, i share some other link
Check this