Consider the following BNF grammar:

A -> I = E

E -> P O P | P

O -> + | - | * | / | **

P -> I | L | UI | UL | (E)

U -> + | - | !

I -> C | CI

C -> a | b | ... | y | z

L -> D | DL

D -> 0 | 1 | ... | 8 | 9

Using the technique described in class implement a recursive descent parser that recognizes strings in this language. Input should be from a file called input.txt and output should be to a file called output.txt. An example session might look like this (these strings are not necessarily in the language):

Input file:

a=1

a=a+b-c*d

a=a//b++c

Output file:

The string "a=1" is in the language.

The string "a=a+b-c*d" is in the language.

The string "a=a//b++c" is not in the language.

You must implement the project inC++

To simplify things, you will not have to handle whitespace when parsing the string, i.e. "" and similar are illegal characters in this language.

All strings should read from a file called "input.txt" and written to a file called "output.txt".