adding 4.

0x11-singly_linked_lists/4-main.c

@@ -0,0 +1,25 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "lists.h"
+
+/**
+ * main - check the code for Holberton School students.
+ *
+ * Return: Always 0.
+ */
+int main(void)
+{
+    list_t *head;
+
+    head = NULL;
+    add_node_end(&head, "Jennie");
+    add_node_end(&head, "&");
+    add_node_end(&head, "Jay");
+    add_node_end(&head, "love");
+    add_node_end(&head, "asm");
+    print_list(head);
+    free_list(head);
+    head = NULL;
+    return (0);
+}

0x11-singly_linked_lists/lists.h

@@ -23,5 +23,6 @@ size_t print_list(const list_t *h);
 size_t list_len(const list_t *h);
 list_t *add_node(list_t **head, const char *str);
 list_t *add_node_end(list_t **head, const char *str);
+void free_list(list_t *head);
 
 #endif