From e2b0f73d1ad81cdfdc81bd7c2d73aca7307c8248 Mon Sep 17 00:00:00 2001
From: lukas-heiligenbrunner <lukas.heiligenbrunner@gmail.com>
Date: Mon, 25 Apr 2022 16:13:48 +0200
Subject: [PATCH] init

---
 CMakeLists.txt |   6 ++
 main.c         | 151 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 157 insertions(+)
 create mode 100644 CMakeLists.txt
 create mode 100644 main.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..2e6d24b
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.22)
+project(untitled C)
+
+set(CMAKE_C_STANDARD 99)
+
+add_executable(untitled main.c)
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..766818f
--- /dev/null
+++ b/main.c
@@ -0,0 +1,151 @@
+#include <stdio.h>
+#include <malloc.h>
+#include <limits.h>
+
+struct Node {
+    struct Node *next;
+    struct Node *prev;
+    void *dta;
+};
+typedef struct Node Node;
+
+typedef struct {
+    Node *head;
+    unsigned length;
+} List;
+
+List *newList() {
+    List *list = malloc(sizeof(List));
+    return list;
+}
+
+Node *_newNode(Node *next, Node *prev, void *dta) {
+    Node *newnode = malloc(sizeof(Node));
+    newnode->next = next;
+    newnode->prev = prev;
+    newnode->dta = dta;
+    return newnode;
+}
+
+Node *_traverseToLast(Node *node) {
+    if (node->next != NULL) {
+        return _traverseToLast(node->next);
+    } else {
+        return node;
+    }
+}
+
+Node *_traverseToPos(Node *node, int pos) {
+    if (pos > 0) {
+        if (node->next != NULL) {
+            return _traverseToPos(node->next, pos - 1);
+        } else {
+            return NULL;
+        }
+    } else {
+        return node;
+    }
+}
+
+void append(List *list, void *elem) {
+    if (list->head == NULL) {
+        // create head
+        list->head = _newNode(NULL, NULL, elem);
+    } else {
+        // append element
+        Node *last = _traverseToLast(list->head);
+        last->next = _newNode(NULL, last, elem);
+    }
+}
+
+int _length(Node *node) {
+    if (node->next == NULL) {
+        return 1;
+    } else {
+        return 1 + _length(node->next);
+    }
+}
+
+int length(List *list) {
+    if (list->head == NULL) {
+        return 0;
+    }
+    return _length(list->head);
+}
+
+void insert(List *list, int position) {
+
+}
+
+void delete(List *list, int position) {
+    Node *todel = _traverseToPos(list->head, position);
+
+    if (todel->prev == NULL) {
+        // we are the header
+        list->head = todel->next;
+        if (list->head != NULL) {
+            list->head->prev = NULL;
+        }
+    } else if (todel->next == NULL) {
+        // we are the last item
+        todel->prev->next = NULL;
+    } else {
+        todel->prev->next = todel->next;
+        todel->next->prev = todel->prev;
+    }
+
+    free(todel);
+}
+
+void deleteAll(List *list) {
+    while (list->head != NULL) {
+        delete(list, 0);
+    }
+}
+
+void deleteList(List *list) {
+    deleteAll(list);
+    free(list);
+}
+
+List *merge(List *list1, List *list2) {
+    return NULL;
+}
+
+void *first(List *list) {
+    return list->head->dta;
+}
+
+void *last(List *list) {
+    return _traverseToLast(list->head)->dta;
+}
+
+void print(List *list, char *typeFormatter) {
+    Node *curr = list->head;
+    while (curr != NULL) {
+        printf(typeFormatter, curr->dta);
+        printf("\n");
+
+        curr = curr->next;
+    }
+}
+
+int main() {
+    printf("Hello, World!\n");
+    List *mylist = newList();
+
+    append(mylist, "test");
+    append(mylist, "test2");
+    append(mylist, "test3");
+    print(mylist, "%s");
+    printf("length is: %d\n", length(mylist));
+
+    printf("\n");
+
+    deleteAll(mylist);
+    printf("length is: %d\n", length(mylist));
+    print(mylist, "%s");
+
+    deleteList(mylist);
+    return 0;
+}