gistfile1.c

#include <stdio.h>
#include <stdlib.h>

struct list {
    int val;
    struct list *next;
};

list *map(list *list, int (*fn)(int))
{
	typedef struct list list;

	list *first = new list;
	first->next = list;
	first->val = val;
	return first;
}

int main()
{
	fn = &square;
}

int square(int n) {
    return n * n;
}