Merge pull request #295 from Rounak14/master

doublyLL.c

Author: probot-auto-merge[bot]

Linked List/doublyLL.c

@@ -0,0 +1,84 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct _node
+{
+	int val;
+	struct _node *prev,*next;
+}node;
+
+node *makenode(int);
+void print(node *);
+node *append(node *,node **,int);
+
+void main()
+{
+	node *start='\0',*last='\0',*nd;
+	int n;
+	while(1)
+	{
+		printf("\nEnter an item : ");
+		scanf("%d",&n);
+		if(n==0)
+		{
+			break;
+		}
+		start=append(start,&last,n);
+	}
+	print(start);
+
+}
+
+void print(node *ptr)
+{
+	if(ptr&&ptr->next)
+	{
+		while(ptr)
+		{
+			printf("%d ",ptr->val);
+			ptr=ptr->next;
+		}
+		printf("\n");
+	}
+	else
+	{
+		while(ptr)
+		{
+			printf("%d ",ptr->val);
+			ptr=ptr->prev;
+		}
+		printf("\n");
+	}
+}
+
+node *makenode(int n)
+{
+	node *nd;
+	nd=(node *)malloc(sizeof(node));
+	nd->val=n;
+	nd->prev=nd->next='\0';
+	return nd;
+}
+node *append(node *start,node **last,int n)
+{
+	node *nd,*ptr;
+	ptr=start;
+	if(ptr=='\0')
+	{
+		nd=makenode(n);
+		start=nd;
+		*last=nd;
+	}
+	else
+	{
+		while(ptr!=*last)
+		{
+			ptr=ptr->next;
+		}
+		nd=makenode(n);
+		ptr->next=nd;
+		nd->prev=ptr;
+		*last=nd;
+	}
+	return start;
+}