I have been learning java only for two weeks. I have to prepare a
simple calculator. If the name of the file "calc 3 4 +" then the
calculator must show the result 7. But if one of these parameters
are missing then the program must shut down and must give an error
like missing parameter. Also if the name of the document is "calc 3
4 5" then program must again show down and must state wrong
parameter.

How can I prepare such program.