Question

Consider the following grammar and their syntax Directed Translation (SDT) rules.
$\text{S}\to \text{S * A {S.val = S.val}\times \text{A.val}}\text{S}\to \text{A {S.val = A.val}}\text{A}\to \text{A + B {A.val = A.val - B.val}}\text{B}\to \text{(S) {B.val = 2}}\text{A}\to \text{B {A.val = B.val}}\text{B}\to \text{id {B.val = id.val}}$

$S_1:\text{Given SDT is L- attributed and using L- attributed evaluation the value of the expression}\text{4*6+3 * 7}is84.S_2:\text{Given SDT is S- attributed and using S-attributed evaluatin value of the expression}4\ast 6+3\ast 7is84.$
Which of the above statements are true with respect to above SDT.

• A. Only $S_2$
• B. Only $S_1$
• C. None of the above
• D. Both $S_1$ and $S_2$

Answer 1

The correct option is D Both $S_1$ and $S_2$

$\text{Given SDT is L-attributee and S-attributee both, all the translation rules are written at the right}\text{end and there is no inherited attribute.}\text{Expression}4\ast 6+3\ast 7$


$\text{Value of teh expression is 84.}\text{So both}{S}_1\text{and}{S}_2\text{is correct}$