Your "struct menu" statement is incomplete. The compiler won't be able to get past that until you complete the statement.
Let me tell you how professionals write code. They write a FEW lines at a time - 4-5 is not unknown - then compile it and look for errors, fix them, then run the code and make sure it works. Then they write a few more lines - again maybe 4-5, maybe more, maybe less, then compile and run. It looks like you're trying to write the whole program before compiling it.
Get the code you have written so far working, THEN we'll look at how to add calculations. Post your reply here; do not keep creating new threads.