Finishing first problem

lab12/1.c

@@ -1 +1,69 @@
-// to do
+#include <stdio.h>
+#include <stdlib.h>
+
+/* Double Linked list related code */
+
+typedef struct _dilist * Dlist;
+
+struct _dilist {
+    int element;
+    Dlist next;
+    Dlist prev;
+};
+
+Dlist insert(int element, Dlist list) {
+    Dlist * addr = &list;
+    Dlist prev = NULL;
+    while (*addr) { // While addr' not null, go to the end.
+    if ( !(*addr)->next ) {
+        prev = *addr;
+    }
+        addr = &(*addr)->next; // the list is modified by this. I think...
+    } // we should be at the end now.
+    Dlist node = malloc(sizeof(struct _dilist));
+    node->element = element;
+    node->next = NULL; // we set to head if we want circular, I think?
+    node->prev = prev; // 1 - NULL, 2 - 1, 3- 2, 4 - 3
+    // printf("%d", prev->element);
+    *addr = node;
+    return list;
+}
+
+void print_list(Dlist list) {
+    printf("DLIST PRINT\n");
+    Dlist * addr = &list;
+    while (*addr) {
+        // if (((*addr)->prev))
+            // printf("prev %d\n", ((*addr)->prev)->element);
+        printf("%d ", (*addr)->element);
+        addr = &(*addr)->next;
+    }
+    printf("\n");
+}
+
+Dlist reverse(Dlist list) {
+  short virgin = 1;
+  // creeaza spatiu pentru lista aia noua
+  Dlist reversed = malloc(sizeof(struct _dilist)); // shoul find better names
+  // sa duce la ultimu element
+  while(list->next) { list = list->next; }
+  while(list) {
+    if (virgin) {
+      reversed = insert(list->element, NULL);
+      virgin = 0;
+    } else {
+      reversed = insert(list->element, reversed);
+    }
+    list = list->prev;
+  }
+  return reversed;
+}
+
+int main(void) {
+  Dlist dli = insert(1, insert(2, insert(3, insert(4, NULL))));
+  Dlist dli2 = reverse(dli);
+  print_list(dli);
+  print_list(dli2);
+  print_list(dli);
+  return 0;
+}