Question

The grammar S → aSa | bS | c is?

(a) LL(1) but not LR(1)

(b) LR(1) but not LR(1)

(c) Both LL(1) but not LR(1) & LR(1) but not LR(1)

(d) None of the mentioned

I had been asked this question in an interview for job.

The query is from Error Recovery in LR phase in section Error Handling of Compiler

Answer 1

Correct option is (c) Both LL(1) but not LR(1) & LR(1) but not LR(1)

Explanation: First(aSa) = a

First(bS) = b

First(c) = c

LR parsers are more powerful than LL (1) parsers and LR (1).