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

#define N 10

/*-------------------------------------------------------------------*/
/* Definition of new types                                           */
enum bool { FALSE = 45, TRUE = 73
};
typedef enum bool Bool;

typedef int Index;

typedef int Item;		/* The content of the list          */

typedef Index List;

struct cell {
    Item value;
    List next;
};
typedef struct cell Cell;

typedef Cell Memory[N];

Memory memory;

const List nil = -1;

Index next_empty_cell_index = 0;

/*-------------------------------------------------------------------*/
/* Function definition                                               */

/* Provide the next index available in Memory                        */
Index allocate(void)
{
    //...
}


/* Add  value x to  list l                                           */
List cons(Item x, List l)
{
    //...
}

Bool is_empty(List l)
{
    //...
}

Item head(List l)
{
    //...
}

List tail(List l)
{
    //...
}


/*************** Derived functions ****************/
void print(List l)
{
    //...
}

int length(List l)
{
    //...
}

Bool search(Item x, List l)
{
    //...
}

int count(Item x, List l)
{
    //...
}


/*-------------------------------------------------------------------*/
/* Main Program                                                      */
int main(int argc, char **argv)
{
    Item x;
    int i, k;
    List l;
    l = cons(1, cons(2, cons(3, nil)));
    print(l);
    l = tail(l);
    print(l);

    if (argc == 2) {
	k = atoi(argv[1]);	/* convert the first argument into an integer */
	assert(k > 0);
    } else
	k = 5;

    for (i = 1; i < k; i++) {
	l = cons(i, l);
	print(l);
    }


    printf("Length of the list: %d\n", length(l));
    x = 7;
    if (search(x, l) == TRUE)
	printf("Element %d is in the list\n", x);

    else
	printf("Element %d is NOT in the list\n", x);
    x = 3;
    printf("Element %d occurs %d times in the list\n", x, count(x, l));
    return 0;
}