Lab 4

Lab 4 (10 points)

 

Write a program that uses stacks to evaluate valid prefix
and postfix arithmetic expressions. Use either the Java API Stack class or one
of the textbook implementations. An algorithm to evaluate postfix expression is
given in your notes and in the book; you will have to devise your own prefix
algorithm. The program should:

-  present the user
with each option (prefix or postfix)

-  prompt for an
expression of the chosen type

-  verify that the
expression is properly formed

-  present the
solution

-  give the user the
opportunity to quit or start over

 

Extra credit options:

5 points: implement the algorithm found in the book and in
the notes to convert an infix expression to postfix, then evaluate the
expression (this option should then be included in the initial menu presented
to the user)

5 points (each): Before presenting the solution, show the
pre- or post-fix expression in infix form, parenthesized as necessary.
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