Accessing const int MAX value from helpers.c

Question

I am trying to implement the hacker3 sorting algorithm. The one that requires a O(n). I think I have figured out the algorithm but I won't spoil it by posting any code here.

My question is regarding to the inputs. It says that we are not allowed to change the definition of the functions and that the maximum available value constant can be used. I should mention here that the number is given as a const int and is not defined as an alias.

The problem arises at the point where we need to access that number from a library declared before the number. The only solution I figured out was to re-declare it in the library, this implies that a change of that number per-compilation would be impossible to detect. Is there any way to actually access it? Or should we just live with the re-declaration?

Answer 1

Apparently, you need to access the constant global int namely MAX which is defined in find.c from other source files. You could do something similar to that

mod1.c

#include <stdio.h>

extern int MAX; // declare MAX to be used externally in mod1.c

void foo(void)
{
    printf("MAX from foo is %i\n", MAX); // access MAX from mod1.c
}

mod1.h

void foo(void); // declare foo

mod2.c

#include <stdio.h>

extern int MAX; // declare MAX to be used externally in mod2.c

void bar(void)
{
    printf("MAX from bar is %i\n", MAX); // access MAX from mod2.c
}

mod2.h

void bar(void); // declare bar

main.c

#include <stdio.h>
#include "mod1.h"
#include "mod2.h"

int MAX = 65536; // define MAX

int main(void)
{
    printf("MAX from main is %i\n", max);
    foo();
    bar();
}

Output:

MAX from main is 65536
MAX from foo is 65536
MAX from bar is 65536

You may refer to this answer for more information on the topic!