UGC-NET | UGC-NET CS 2017 Dec 2 | Question 34
Which of the following statements is/are TRUE ?
(i) The grammar S → SS | a is ambiguous (where S is the start symbol).
(ii) The grammar S → 0S1 | 01S | e is ambiguous (the special symbol e represents the empty string and S is the start symbol).
(iii) The grammar (where S is the start symbol).
S → T/U T → x S y ? xy ? e U → yT
generates a language consisting of the string yxxyy.
(A) Only (i) and (ii) are TRUE
(B) Only (i) and (iii) are TRUE
(C) Only (ii) and (iii) are TRUE
(D) All of (i), (ii) and (iii) are TRUE
Explanation: We can generate more than 1 parse tree for a single string from the grammars. For statement (iii)
S → U U → yT yT → yxSy yxSy → yxTy yxTy → yxxyy
All statement are correct.
So, option (D) is correct.
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