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Date Posted: 7/14/2008 9:21:26 PM  Status: Live
CFG
Course Textbook Chapter Problem
N/A theory of automata N/A N/A
Question Details:
 

Question  Give context free grammars generating the following languages.

           {w#w | wR is a substring of x for w, x ? {0, 1}*}

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Date Posted: 7/14/2008 9:50:48 PM  Status: Live
Asker's Rating: None Provided    Moderator's Rating: Somewhat Helpful
Response:
hi frnd,

Give unambiguous context-free grammars for each of the following languages:
  1. The language of identifiers, whose elements are sequences of letters or digits, starting with a letter
  2. The language of natural numbers, whose elements are sequences of digits, starting with a digit different from 0
  3. The language of real numbers, in which either the integer part or the fractional part can be empty, but not both. Thus the grammar must allow 12., 1.2, .12, but not a decimal point by itself.



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Date Posted: 7/24/2008 5:44:40 AM  Status: Live
Asker's Rating: None Provided    Moderator's Rating: N/A
Response:
Dear User,

Context free grammar :
         S AB
         A 0A0|1A1|X
         B 0B|1B0|0|1|ε
         X X0|X1|$



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