= {a, b}, the following program fragment does the trick, then goes to state
q1.
Just
as the productions are the "heart" of a grammar, in that most of the
other components can be figured out by looking at the productions, the transitions
are the heart of a Turing machine. These transitions are often given as a table
or list of 5-tuples, where each tuple has the form
Creating such a list is often spoken of as "programming" a Turing machine.
A Turing machine is often defined to start with the read head positioned over
the first (leftmost) input symbol. This isn't really necessary, because if the
Turing machine starts anywhere on the nonblank portion of the tape, it's simple
to get to the first input symbol. For the input alphabet
= {a, b}, the following program fragment does the trick, then goes to state
q1.
(q0, a, a, L, q0)
(q0, b, b, L, q0)
(q0, #, #, R, q1)