For this assignment, rework your derivative program into a more object-oriented form. Build a separate file for each kind of expression. All of the operations on a given kind of expression should be put together.
Get files Expression.ast, VarExpr.ast, ConstExpr.ast and SumExpr.ast, implementing the concepts of Expression (a general expression), a variable, a constant and a sum, respectively. Look at them as examples of how to write your new files. Also get TestExpr.ast, which contains some tests of these. All are in directory /export/stu/3675/deriv.
Add new files to cover difference, products and constant powers.
You should not have to modify files VarExpr.ast, ConstExpr.ast, SumExpr.ast or Expression.ast at all in order to write your new files. Just add new files. The tester will need to be modified, to make it do more tests.