circular doubly linked list, not done yet

2 files changed, 86 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index bf658a9..13d1cff 100644
--- a/Makefile
+++ b/Makefile
@@ -4,33 +4,36 @@ CFLAGS=-O3 -flto -march=native -DNDEBUG -fomit-frame-pointer -s -std=gnu99
 TARGET1=s_linkedlist
 TARGET2=d_linkedlist
 TARGET3=cs_linkedlist
+TARGET4=cd_linkedlist
 TESTTARGET1=s_linkedlist-t
 TESTTARGET2=d_linkedlist-t
 TESTTARGET3=cs_linkedlist-t
+TESTTARGET4=cd_linkedlist-t
 INSTALL_DIRECTORY=/usr/local/bin
 MAKEFLAGS += -s
 SRCSL=s_linkedlist.c
 SRCDL=d_linkedlist.c
 SRCCSL=cs_linkedlist.c
+SRCCDL=cd_linkedlist.c
 
 all: release
 clean:
-	rm -f $(TARGET1) $(TARGET2) $(TARGET3)
-	rm -f test/$(TESTTARGET1) test/$(TESTTARGET2) test/$(TESTTARGET3)
+	rm -f $(TARGET1) $(TARGET2) $(TARGET3) $(TARGET4)
+	rm -f test/$(TESTTARGET1) test/$(TESTTARGET2) test/$(TESTTARGET3) test/$(TESTTARGET4)
 
 tests:
 	
 	$(CC) $(CFLAGS_TESTBIN) $(SRCSL) -o test/$(TESTTARGET1)
 	$(CC) $(CFLAGS_TESTBIN) $(SRCDL) -o test/$(TESTTARGET2)
 	$(CC) $(CFLAGS_TESTBIN) $(SRCCSL) -o test/$(TESTTARGET3)	
-	
+	$(CC) $(CFLAGS_TESTBIN) $(SRCCDL) -o test/$(TESTTARGET4)
 
 release:
 	
 	$(CC) $(CFLAGS) $(SRCSL) -o $(TARGET1)
 	$(CC) $(CFLAGS) $(SRCDL) -o $(TARGET2)
 	$(CC) $(CFLAGS) $(SRCCSL) -o $(TARGET3)
-	
+	$(CC) $(CFLAGS) $(SRCCSL) -o $(TARGET4)
 	
 
 	
diff --git a/cd_linkedlist.c b/cd_linkedlist.c
index e69de29..a1226fd 100644
--- a/cd_linkedlist.c
+++ b/cd_linkedlist.c
@@ -0,0 +1,79 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+// circular doubly 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 *yet*
+    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 = head;
+	    head->prev = wr1;
+	} 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
+        
+    }
+
+    
+    return head;
+}
+
+void freellist(struct waster *wr1) {
+    
+    struct waster *head = wr1;
+    struct waster *save;
+    while (wr1->next != head) {
+        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;
+}