Reference no: EM13708707

Question: Solve these problems any help would be much appreciated!

Part 1:  The subsequent grammar, is ambiguous.

      <S> à if <E> then <S> | if <E> then <S> else <S> | <statements without if>

      <E> à e1 | e2 | . . . | en

Show that the grammar is unambiguous; how does it attach the else statement? If this is not the attachment you wanted, how would you need to write the code?

Part 2: Given the subsequent code fragment, where x is a number.

{ y >= 0 }

z = 0

n = y

while (n > 0) begin

    z = z + x

    n = n - 1

end

What does it compute? Prove it, showing how you derive the loop invariant.

Can you show that the grammar is unambiguous?