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I’m having trouble getting JFlap to work on my computer. What should I do?
See the following sections of the assignment:
My FSM looks correct, but it doesn’t accept the right output. What should I do?
Be sure that none of your transition labels have spaces in them. If this doesn’t fix the issue, try stepping through the FSM for a specific input string and see where its behavior deviates from what you expect.
I’m stuck on problem 3. Any suggestions?
We discussed this problem during lecture on April 23. We recommend that you review our discussion from that lecture.
It’s important not to over-complicate this problem. A few people have asked if we can solve this one with less than eight states, and we mentioned in lecture that doing so is impossible. Therefore, we recommend that you start with the eight states described in the lecture notes.
If we only care about the third-to-last bit, we can assume that we
always start with a string of three zeroes (the state labeled s000
in the notes). Then we just need to draw in the transitions,
remembering that every state should have a transition for 0 and a
transition for 1.
Suppose we are at s000. This means the last three digits in the
string are all zeroes. We need to draw a transition from this state
for 0 and for 1. Answering the following questions will help you
figure out which states to transition to:
If my string ends with 000 and I add a 0 to the end, which
state should I go to?
If my string ends with 000 and I add a 1 to the end, which
state should I go to?
Repeating this process for all eight states will give you a complete FSM that accepts strings where the third to last bit is 1. Just remember that each state represents the last three letters of your string.
Last updated on April 28, 2025.