Engineering Questions with Answers - Multiple Choice Questions

# Expression Tree Multiple Choice MCQ

1 - Question

The leaves of an expression tree always contain?
a) operators
b) operands
c) null
d) expression

Explanation: The leaves of an expression tree always contain the result of a given expression (i.e.) operands.

2 - Question

A node can have a minimum of one child.
a) true
b) false

Explanation: It is possible for a node to have at least one child, as is the case with the unary minus operator.

3 - Question

What does the other nodes of an expression tree(except leaves) contain?
a) only operands
b) only operators
c) both operands and operators
d) expression

Explanation: The nodes other than leaves always contain only operators. There cannot be any operand in those nodes.

4 - Question

An expression tree is a kind of?
a) Binary search tree
b) Fibonacci tree
c) Binary tree
d) Treap

Explanation: The expression tree is a binary tree. It contains operands at leaf nodes and remaining nodes are filled with operators. The operands and the operators can be arranged in any order (ascending, descending).

5 - Question

The expression obtained by recursively producing a left expression, followed by an operator, followed by recursively producing a right expression is called?
a) prefix expression
b) infix expression
c) postfix expression
d) paranthesized expression

Explanation: It is an infix expression because the format of an infix expression is given by operand-operator-operand.

6 - Question

The average depth of a binary tree is given as?
a) O(N)
b) O(log N)
c) O(M log N)
d) O(√N)

Explanation: The average depth of a binary expression tree is mathematically found to be O(√N).

7 - Question

Only infix expression can be made into an expression tree.
a) true
b) false

Explanation: All infix, prefix and postfix expressions can be made into an expression tree using appropriate algorithms.

8 - Question

An expression tree is created using?
a) postfix expression
b) prefix expression
c) infix expression
d) paranthesized expression

Explanation: A postfix expression is converted into an expression tree by reading one symbol at a time and constructing a tree respectively.

9 - Question

++a*bc*+defg is an?
a) postfix expression
b) infix expression
c) prefix expression
d) invalid expression

Explanation: It is a prefix expression obtained from a preorder traversal since it is of the form operator-operand-operand.

10 - Question

An expression tree’s nodes can be deleted by calling?
a) malloc
b) calloc
c) delete
d) free

Explanation: In Binary trees, nodes are created by calling malloc and they are deleted by calling free.

11 - Question

What is the postfix expression for the following expression tree? a) abcde++**
b) ab+cde+**
c) abc+de+**
d) abcd+*e+*

Explanation: If the given expression tree is evaluated, the postfix expression ab+cde+** is obtained.

12 - Question

In an expression tree algorithm, what happens when an operand is encountered?
a) create one node pointing to a stack
b) pop the nodes from the stack
c) clear stack
d) merge all the nodes