ISRO | ISRO CS 2015 | Question 24

Given the following expression grammar:

E → E ∗ F ∣ F + E ∣ F
F → F − F ∣ id

Which of the following is true?
(A) * has higher precedence than +
(B) – has higher precedence than *
(C) + and – have same precedence
(D) + has higher precedence than *

Answer: (B)
Explanation: For the above expression grammar both * and + have same precedence which can be seen through the following parse trees:

whereas – operator has a higher precedence from both + and * as, – operator will always be executed first along with the operands stored in id and then * or + will be computed.

So, option (B) is correct.
Quiz of this Question