Given the following expression grammar:
E -> E * F | F + E | F F -> F - F | id
which of the following is true?
(A) * has higher precedence than +
(B) – has higher precedence than *
(C) + and — have same precedence
(D) + has higher precedence than *
Answer: (B)
Explanation: Let say i/p is 3*4-5 when we draw parse tree according to grammar
E
/ | \
E * F
| / | \
F F - F
| | |
id(3) id(4) id(5)As we can see first ‘- ‘ will be evaluated then ‘ * ‘ is evaluated so ‘ – ‘ has higher precedence then *.
So correct choice is B
See question 1 of https://www.geeksforgeeks.org/compilers-set-2/amp/
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