Question

Recursive Descent Parsing

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):

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 in C++ Implementations that do not include a solution in language will, at best, receive half credit. To simplify things you will not have to handle whitespace when parsing the string, i.e. " " and similiar are illegal characters in this language. All strings should read from a file called "input.txt" and written to a file called "output.txt".

input.txt file will be

a=+0
a=!b
a=b+0
a=b++c
a=b**c
a=(((b)))
a=((b+c)*(d+e))
a=b+
a=b+c*d
a=b+c*d^e
a=(b+c)*(d+e))
a=((b+c)*(d+e)

Answer 1