listops.c

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

//#define MAXVAL 99
//#define MINVAL 1
#define MAXID 7



typedef struct cus_rec_t data_t;
typedef struct node node_t;

struct cus_rec_t {
    char cus_ID_rep[MAXID];
    int* visits;
};

struct node {
	data_t data;
	node_t *next;
};

typedef struct {
	node_t *head;
	node_t *foot;
} list_t;

list_t
*make_empty_list(void) {
	list_t *list;
	list = (list_t*)malloc(sizeof(*list));
	assert(list!=NULL);
	list->head = list->foot = NULL;
	return list;
}

void
free_list(list_t *list) {
	node_t *curr, *prev;
	assert(list!=NULL);
	curr = list->head;
	while (curr) {
		prev = curr;
		curr = curr->next;
		free(prev);
	}
	free(list);
}

list_t* 
insert_at_head(list_t *list, data_t value) {
	node_t *new;
	new = (node_t*)malloc(sizeof(*new));
	assert(list!=NULL && new!=NULL);
	new->data = value;
	new->next = list->head;
	list->head = new;
	if (list->foot==NULL) {
		/* this is the first insertion into the list */
		list->foot = new;
	}
	return list;
}

list_t* 
insert_at_foot(list_t *list, data_t value) {
	node_t *new;
	new = (node_t*)malloc(sizeof(*new));
	assert(list!=NULL && new!=NULL);
	new->data = value;
	new->next = NULL;
	if (list->foot==NULL) {
		/* this is the first insertion into the list */
		list->head = list->foot = new;
	} else {
		list->foot->next = new;
		list->foot = new;
	}
	return list;
}