add trivial linked list example

Makefile

@@ -1,7 +1,10 @@
-CFLAGS=-std=c99
+CFLAGS=-std=c99 -Wall -g
 INDENTOPTS=-kr --no-tabs --braces-on-func-def-line --indent-level2
 
-all: approximate-pi
+all: approximate-pi linked-list
+
+clean:
+	rm -f approximate-pi linked-list
 
 .PHONY: indent
 indent:

linked-list.c

@@ -0,0 +1,44 @@
+#include <stdio.h>
+#include "assert.h"
+
+struct list_node {
+  int data;
+  struct list_node *next;
+};
+typedef struct list_node list_node_t;
+
+int list_length(list_node_t * list) {
+  list_node_t *cur;
+  int count = 0;
+
+  cur = list;
+  while (cur != NULL) {
+    count++;
+    cur = cur->next;
+  }
+
+  return count;
+}
+
+void list_print(list_node_t * list) {
+  list_node_t *cur;
+
+  cur = list;
+  while (cur != NULL) {
+    printf("%d ", cur->data);
+    cur = cur->next;
+  }
+  printf("\n");
+}
+
+int main(int argc, char *argv[]) {
+  list_node_t *emptylist = NULL;
+  assert(list_length(emptylist) == 0);
+  list_print(emptylist);
+  printf("list_length = %d\n", list_length(emptylist));
+
+  list_node_t foo = { 1, NULL };
+  assert(list_length(&foo) == 1);
+  list_print(&foo);
+  printf("list_length = %d\n", list_length(&foo));
+}