Implemented doubly linked list, fixed issued with singly linked list. Added some nicer visualization for both of them.

1 files changed, 76 insertions, 0 deletions

diff --git a/d_linkedlist.c b/d_linkedlist.c
new file mode 100644
index 0000000..025bbb9
--- /dev/null
+++ b/d_linkedlist.c
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+// Singly linked list demo
+
+struct waster {
+    int gg;
+    struct waster *prev;
+    struct waster *next;
+};
+
+struct waster *newnode () {
+
+    struct waster *new = malloc(sizeof(struct waster));
+    return new; 
+}
+
+struct waster *llist (uint64_t count) {
+    
+    struct waster *wr1 = malloc(sizeof(struct waster));
+    struct waster *head = wr1;
+    wr1->gg = 0; // Data for first node
+    wr1->prev = NULL; // There is no previous node
+    wr1->next = newnode(); // Make new node, next points to it
+    struct waster *prv = wr1; // Make prv point to current node
+    wr1 = wr1->next; // Make wr1 point to next node
+
+    
+    for (uint64_t i = 1 ; i < count ; i++) { // Actual loop starts
+        
+        wr1->gg = i; // Data for 2nd node
+	wr1->prev = prv; // make prev point to prv = wr1 = last node
+        if (i == count-1) {
+	    wr1->next = NULL;
+	} else {
+	    wr1->next = newnode(); // Make next node, next points to it
+        }
+	prv = wr1; // prv points to current node
+        wr1 = wr1->next; // Make wr1 point to the next node
+        
+    }
+
+    wr1 = NULL;
+    return head;
+}
+
+void freellist(struct waster *wr1) {
+    //printf("freelist \n");
+    struct waster *save;
+    while (wr1 != NULL) {
+        save = wr1;
+        wr1 = wr1->next;
+        free(save);
+    }
+}
+
+int main () {
+
+    struct waster *wr1 = llist(20);
+    struct waster *p;
+    for (p = wr1 ; p != NULL ; p = p->next) {
+        void *prev = (void*)p->prev;
+	void *next = (void*)p->next;
+	printf("\n------%p----------",(void *)p);
+	printf("\ndata: %d\nprev: %p\nnext: %p\n", p->gg, prev, next);
+	printf("-----------------------------\n");
+    }
+    
+    freellist(wr1);
+    return 0;
+}