FIRST set for CFG/grammar in C/C++. input is grammar , output is shown the first set. example input grammer : E -> TR R -> +T R| # T -> F Y Y -> *F Y | # F -> (E) | i Output : First(E)= { (, i, }...

FIRST set  for CFG/grammar  in C/C++.

input  is grammar
, output is shown the first set.

example input grammer :

E -> TR

R -> +T R| #

T -> F Y

Y -> *F Y | #

F -> (E) | i

Output :

First(E)= { (, i, }
First(R)= { +, #, }
First(T)= { (, i, }
First(Y)= { *, #, }
First(F)= { (, i, }

Assumptions :

1. Epsilon is represented by ‘#’.


2. Productions are of the form A=B, where ‘A’ is a single Non-Terminal and ‘B’ can be any combination of Terminals and Non- Terminals.


3. L.H.S. of the first production rule is the start symbol.


4. Grammar is not left recursive.


5. Each production of a non-terminal is entered on a different line.


6. Only Upper Case letters are Non-Terminals and everything else is a terminal.


7. Do not use ‘!’ or ‘$’ as they are reserved for special purposes.