1. NFA: Vending Machine Simulation
Steven Stockall

2. Intro
NFA-Nondeterministic Finite Automaton - several possible states from current state, type of finite state machine
Goals:
Create a function NFA that works in a simulation
Gain a greater understanding to the use of and applications for finite state machines
Applications:
Vending Machine
Elevator
Circuit hardware

3. Design Machine accepts dimes, nickels, and quarters
Monetary cap of $1
Monetary states for all valid change inputs
Several purchase options:
Purchase items will vary in price
Invalid selections will return to current monetary state with prompt stating invalid selection
Valid selections will drop item and return correct change
‘coin return’ button:
Returns change
Overflow:
Monertary input over $1 will be handled with an overflow state, this returns the amount of change equal to the amount over $1 entered into the machine by the user

4. Design (cont.) Code: Design will be implemented in C#
Design will have a small user interactive window with which the user can interact with and test the program

5. Code Organization Main that starts the core program Core:
Program starts with a $.00 state
based on user input will call one of the modules passing in the user input and the old state
modules will return new state
Module that handles monetary selection:
overflow will be handled within module
Module that handles item selection:
invalid selections return same state
valid selections return item adjust change amount and returns remaining change then returns to $.00 state
Module that handles coin return:
Returns coins
Returns to $.00 state

6. Testing Correct State transition: Correct State chaining:
test to check state to state transition
Correct State chaining:
test to check state transitions are correct for long transition chains
Correct input handling:
Buttons work properly
Correct cash overflow handling:
purposely test all possible overflow states

7. Conclusion
Goals:
will be to see how a NFA works in real world applications
create a functioning NFA
create a workable vending machine simulation