MCQ IN COMPUTER SCIENCE & ENGINEERING

Detailed explanation-1: -1. A push down automaton employs data structure. Explanation: A push down automata uses a stack to carry out its operations. They are more capable than the finite automatons but less than the turing model.

Detailed explanation-2: -A pushdown automaton (PDA) is a type of automaton that employs a Stack. Pushdown automata are used in theories about what can be computed by machines. They are more capable than finite state machines but less capable than Turing machines.

Detailed explanation-3: -Stack: The stack is a structure in which we can push and remove the items from one end only. It has an infinite size. In PDA, the stack is used to store the items temporarily.

Detailed explanation-4: -The term “pushdown” refers to the fact that the stack can be regarded as being “pushed down” like a tray dispenser at a cafeteria, since the operations never work on elements other than the top element. A stack automaton, by contrast, does allow access to and operations on deeper elements.

Detailed explanation-5: -A push down automata (PDA) is a way to implement a context free grammar (CFG) in a similar way to design the deterministic finite automata (DFA) for a regular grammar. A DFA can remember a finite amount of information but a PDA can remember an infinite amount of information.