Question

Instantaneous description of a counter machine can be described using:

(a) the input tape contents

(b) position of the input head

(c) distance of storage heads from symbol Z

(d) all of the mentioned

This question was posed to me during a job interview.

This interesting question is from Multistack Machines, Counter Machines in section Introduction to Turing Machines of Automata Theory

Answer 1

The correct choice is (d) all of the mentioned

The explanation is: Instantaneous description of a counter machine can be described by the state, the input tape contents, the position of input head, and the distance of storage heads from the symbol Z. The counter machine can really store a count on each tape and tell if the count is zero.