Q:

What is the use function in c++?

I'm currently reading a c++ book and one of the function is 
void fp(char v[]){
   for(char* p = v; *p!=0;p++) use(*p);
}

I wrote this into my editor and compiled it. I also included the headers
#include <iostream>
#include <string.h>

But my terminal returns the following message:
use of undeclared identifier 'use'

I also google it and its nowhere to be found online, the function doesn't exist.

A:

That's because there is no such standard library function.
The author is either using pseudo-code here, or has defined this function somewhere else in the book.

