## Regular expression for 0 or more occurrence of either a or b or both

Regular expression for 0 or more occurrence of either a or b or both => (a+b)*

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Regular expression for 0 or more occurrence of either a or b or both

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Regular expression for all binary string

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Regular expression for string having zero or more a

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Regular expression over ∑={a,b,c} that represent all string of length 3

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Define predictive parsers

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Define recursive-descent parser

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What are the problems in top down parsing

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Define ambiguity

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Define context-free language

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Write a grammar to define simple arithmetic expression

Regular expression for 0 or more occurrence of either a or b or both => (a+b)*

All binary string. => (0+1)*

Regular expression for String having zero or more a => a*

Regular expression over ∑={a,b,c} that represent all string of length 3 => (a+b+c)(a+b+c)(a+b+c)

A predictive parser is an efficient way of implementing recursive_descent parsing by handling the stack of activation records explicitly. The predictive parser has an input, a stack , a parsing…

A parser that uses a set of recursive procedures to recognize its input with non backtracking is called a recursive-descent parser. The recursive procedures can be quite easy to write.

The problems in top down parsinga) Left recursion.b) Backtracking.c) The order in which alternates are tried can affect the language accepted.

A grammar that produces more than one parse tree for some sentence is said to be ambiguous. An ambiguous grammar is one that produces more than one leftmost or more…

Given a grammar G with start symbol S, we can use the ==> relation to define L(G) , the language generated by G. We say a string of terminals w…

Grammar to define simple arithmetic expressionexpr ->expr op exprexpr ->(expr)expr -> – exprexpr ->idop -> + | – | * | / | ^