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Its very easy to find FIRST in compiler design. Im finding difficult to find follow , suppose if we have one variable(say B) then we need to search the variable in the whole question .If there was a terminal or a variable after B (say Ba,BA) we can find it easily. but if we have epsilon (say Bε).How to find the follow for such values(Bε) and if there was ε in the same variable then we need to go to the next variable.then how to continue the problem. help me to find the solution for the following question.

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For production of the form $A \rightarrow \alpha B \beta,\ FOLLOW(B) = FIRST(\beta)-\{\epsilon\}$.

If $\epsilon$ belong to $FIRST(\beta)$ or in case the production is of the for $A \rightarrow \alpha B$, whatever is in $FOLLOW(A)$ must be in $FOLLOW(B)$

Exercise

Find $FIRST\ \&\ FOLLOW$ of all the symbols in the grammar $G = \{\{S,B,C\},\{a,b\},P,S\}$, where $S$ is the start symbol and $P$ is the set of productions given below.

\begin{align*} S \rightarrow BC\\ B \rightarrow aB\ |\ \epsilon\\ C \rightarrow bC\ |\ \epsilon\\ \end{align*}

Drop a comment in case you need a more detailed explanation. However, I encourage you to solve the exercise problem first.

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