Question

Which of the functions are not performed by the turing machine after reading a symbol?

(a) writes the symbol

(b) moves the tape one cell left/right

(c) proceeds with next instruction or halts

(d) none of the mentioned

I had been asked this question during an online exam.

Enquiry is from Turing Machine-Notation and Transition Diagrams topic in division Introduction to Turing Machines of Automata Theory

Answer 1

Right choice is (d) none of the mentioned

For explanation I would say: After the read head  reads the symbol from the input tape, it performs the following functions:

a) writes a symbol(some model allow symbol erasure/no writing)

b) moves the tape left or right (some models allows no motion)

c) proceeds with subsequent instruction or goes either into accepting halting state or rejecting halting state.