ISRO2020-35

Question

Given the grammar

• $s \rightarrow T ^{\ast} S\ \mid T$
• $T \rightarrow U+T\ \mid U$
• $U \rightarrow a  \mid b$

Which of the following statements is wrong?

• A. Grammar is not ambiguous
• B. Priority of $+$ over $^{\ast}$ is ensured
• C. Right to left evaluation of $^{\ast}$ and $+$ happens
• D. None of these

Answer 1

Answer: D) None of these.

a. Grammar is not ambiguous - true

b. Priority of + is > than *,  since + comes lower in parse tree - true.

c. Right associativity - true

Answer 2

Priority of + over ∗ is ensured as plus is at a lower level as compared to *  Also both are right recursive and therefore they are right-associative

Answer 3

Option D) None of these is the correct answer,

a) Grammar is not ambiguous, True

​​​​​​​b) + is having higher priority than * .

​​​​​​​​​​​​​​c) both + and * are right associative.