Programming

Which of the following is a linear data structure?

• Array

• AVL trees

• Binary Tree

• Graphs

Process of removing an element from stack is called__?

• Create
  

• Push
  

• Evaluation
  

• Pop

Which one of the following statements is TRUE about the time complexity of algorithms that solve the above problem in O(1) space?

• It is not possible to reverse a singly linked list in O(1) space.

What is the difference between Queue and Stack?

• a) Stack is LIFO; Queue is FIFO
  

• b) Queue is LIFO; Stack is FIFO
  

• c) Stack and Queue is FIFO
  

• d) Stack and Queue is LIFO

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

• a) push and pop
  

• b) enqueue and dequeue
  

• c) enqueue and peek
  

• d) add and remove

In a stack, if a user tries to remove an element from an empty

stack it is called __?

• Overflow
  
  

• Empty collection
  

• Underflow
  

• Garbage Collection

Answer explanation

Underflow occurs when the user performs a pop operation on an empty stack. Overflow occurs when the stack is full and the user performs a push operation. Garbage Collection is used to recover the memory occupied by objects that are no longer used

Where does a new element be inserted in linked list implementation of a queue?

• a) Head of list
  

• b) Tail of list
  

• c) At the centre of list
  

• d) All the old entries are pushed and then the new element is inserted

Answer explanation

To maintain FIFO, newer elements are inserted to the tail of the list.

public class Solution{ public static void main(String[] args)

{ short x = 10; x = x * 5; System.out.print(x); } }

• 50

• 10

• Compile Error

• Expection

String str = “Hellow”;

System.out.println(str.indexOf(‘t));

what is the output of this code?

• 0

• 1

• true

• -1

<script type="text/javascript" language="javascript"> var a = "Scaler"; var result = a.substring(2, 4); document.write(result); </script>

• al

• ale

• cal

• caler

Answer explanation

The substring function in javascript slices a substring out of a given string from the start to end indexes(excluding the end index). So the 2nd and 3rd characters are taken here(0-based indexing) and the answer is al.