Data Structures Through C C-21 (UNIT 5 & 6)

What is the value of the postfix expression 6 3 2 4 + – *?

• 1

• 30

• -9

• -18

Here is an infix expression: 4 + 3*(6*3-12). Suppose that we are using the usual stack algorithm to convert the expression from infix to postfix notation. The maximum number of symbols that will appear on the stack AT ONE TIME during the conversion of this expression?

• 4

• 3

• 2

• 1

What does ‘stack underflow’ refer to?

• accessing item from an undefined stack

• adding items to a full stack

• removing items from an empty stack

• index out of bounds exception

Which of the following array element will return the top-of-the-stack-element for a stack of size N elements?

• S[N-1]

• S[N]

• S[N-2]

• S[N+1]

Convert the following infix expressions into its equivalent postfix expressions.
(A + B ⋀D)/(E – F)+G

• (A B D ⋀ + E F – / G +)

• (A B D +⋀ E F – / G +)

• (A B D ⋀ + E F/- G +)

• (A B D E F + ⋀ / – G +)

A data structure in which elements can be inserted or deleted at/from both ends but not in the middle is?

• Queue

• Circular queue

• Deque

• Priority queue

What is the need for a circular queue?

• effective usage of memory

• easier computations

• to delete elements based on priority

• implement LIFO principle in queues

What is the correct method used to insert and delete items from the queue?

• push and pop

• enqueue and dequeue

• enqueue and peek

• add and remove

A normal queue, if implemented using an array of size MAX_SIZE, gets full when

• Rear=MAX_SIZE-1

• Front=(rear+1)mod MAX_SIZE

• Front=rear+1

• Rear=front

An array of size MAX_SIZE is used to implement a circular queue. Front, Rear, and count are tracked. Suppose front is 0 and rear is MAX_SIZE -1. How many elements are present in the queue?

• Zero

• One

• MAX_SIZE-1

• MAX_SIZE