Extend the Postfix Calculator ADT as follows:
(a) To perform several unary operations commonly found on scientific calculators: absolute value, square root, sine, cosine, and tangent. The operations should be specified to the compute() method using the following acronyms: abs, sqrt, sin, cos, tan.
(b) To use a second stack on which values can be saved. Add the following two operations to the ADT:
* store(): Removes the top value from the operand stack and pushes it onto the save stack.
* recall(): Removes the top value from the save stack and pushes it onto the operand stack.