evaluating simple arithmetic expression using recursive descent parser - c language

[johnsmith2]

I have a program that evaluates a simple expression in c++ using the recursive descent parser but I want to have the same functionality for a program written in c .
I tried to modify it as a "c" program but it gives too many errors and can not even compile with cc on unix since I used bool ,
any suggestion ?

[Peter87]

#include <stdbool.h>