Compiler Design : Timothy G. Griffin

Question

 

 

4. Consider the following grammar and their syntax directed translation (SDT) rules.

S → S * A        {S.val = S.val x A. val}

S → A              {S.val = A.val}

A → A + B       {A.val = A.val – B.val}

B → (S)’           {B.val = 2}

A → B              {A.val = B.val}

B → id             {B.val = id.val}

 

Calculate the evaluation value of the expression 4 * 6 + 3 * 7. Is it 45 or 84?

 

 

Comments

Ans should be 84 , isn’t it?

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Please explain your answer step by step

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The syntax tree:

The expression will be evaluated as : (4* (6 – 3))* 7 = 84