list_empty/list_add

linked-list.c

@@ -1,4 +1,6 @@
 #include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
 #include "assert.h"
 
 struct list_node {
@@ -20,6 +22,10 @@ int list_length(list_node_t * list) {
   return count;
 }
 
+bool list_empty(list_node_t *list) {
+  return (list == NULL);
+}
+
 void list_print(list_node_t * list) {
   list_node_t *cur;
 
@@ -31,14 +37,50 @@ void list_print(list_node_t * list) {
   printf("\n");
 }
 
+void list_add(list_node_t *list, list_node_t *item) {
+  list_node_t *cur;
+
+  cur = list;
+  assert(cur != NULL);
+  while (cur->next != NULL) {
+    cur = cur->next;
+  }
+
+  cur->next = item;
+}
+
 int main(int argc, char *argv[]) {
   list_node_t *emptylist = NULL;
   assert(list_length(emptylist) == 0);
+  assert(list_empty(emptylist) == true);
   list_print(emptylist);
   printf("list_length = %d\n", list_length(emptylist));
 
   list_node_t foo = { 1, NULL };
+
   assert(list_length(&foo) == 1);
+  assert(list_empty(&foo) == false);
+  list_print(&foo);
+  printf("list_length = %d\n", list_length(&foo));
+
+  // append something to foo
+  list_node_t bar = { 2, NULL };
+  list_add(&foo, &bar);
+
+  assert(list_length(&foo) == 2);
+  assert(list_length(&bar) == 1);
+  list_print(&foo);
+  printf("list_length = %d\n", list_length(&foo));
+
+  // append more
+  const int howmany = 100;
+  for(int i = 0; i < howmany; i++) {
+    list_node_t *newnode = malloc(sizeof(list_node_t));
+    newnode->data = i;
+
+    list_add(&foo, newnode);
+  }
+  assert(list_length(&foo) == 2 + howmany);
   list_print(&foo);
   printf("list_length = %d\n", list_length(&foo));
 }