self doubt

Question

https://gateoverflow.in/86869/gate1990-16a

the given grammar is this 

G1:S→ if S then S else S

        S→ if S then S

and in solution we used a terminal expr 

stmt→ if expr  then stmt 
                           ∣ ifexpr then stmt else stmt 
                           ∣other

 

Comments

I think we can do this, there is no problem.

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BUT HOW I MEAN IF I WILL U G1 THEN NOT TERMINATING REPEATING JUST IN A LOOP