add tasks 5,8

Author: GamilaCoding

0x17-doubly_linked_lists/7-insert_dnodeint.c

@@ -0,0 +1,50 @@
+#include "lists.h"
+
+/**
+  * insert_dnodeint_at_index -  inserts a new node at a given position
+  * @h: header of double linked list
+  * @idx: index of the node, starting from 0
+  * @n: is a given number
+  * Return: a address of nth node
+  */
+dlistint_t *insert_dnodeint_at_index(dlistint_t **h, unsigned int idx, int n)
+{
+	dlistint_t *new, *headcopy = *h;
+	unsigned int i;
+
+	new = malloc(sizeof(dlistint_t));
+	if (new == NULL)
+		return (NULL);
+	new->n = n;
+	while (headcopy != NULL && headcopy->prev != NULL)
+	{
+		headcopy = headcopy->prev;
+		*h = (*h)->prev;
+	}
+	if (idx == 0)
+	{
+		free(new);
+		return (add_dnodeint(h, n));
+	}
+
+	for (i = 0; (i < idx - 1) && headcopy != NULL; i++)
+		headcopy = headcopy->next;
+	if (headcopy == NULL)
+	{
+		free(new);
+		return (NULL);
+	}
+	if (headcopy->next == NULL)
+	{
+		new->next = NULL;
+		new->prev = headcopy;
+		headcopy->next = new;
+	} else
+	{
+		new->next = headcopy->next;
+		new->prev = headcopy;
+		headcopy->next->prev = new;
+		headcopy->next = new;
+	}
+	return (new);
+}

0x17-doubly_linked_lists/7-main.c

@@ -0,0 +1,31 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "lists.h"
+
+/**
+ * main - check the code
+ *
+ * Return: Always EXIT_SUCCESS.
+ */
+int main(void)
+{
+    dlistint_t *head;
+
+    head = NULL;
+    add_dnodeint_end(&head, 0);
+    add_dnodeint_end(&head, 1);
+    add_dnodeint_end(&head, 2);
+    add_dnodeint_end(&head, 3);
+    add_dnodeint_end(&head, 4);
+    add_dnodeint_end(&head, 98);
+    add_dnodeint_end(&head, 402);
+    add_dnodeint_end(&head, 1024);
+    print_dlistint(head);
+    printf("-----------------\n");
+    insert_dnodeint_at_index(&head, 5, 4096);
+    print_dlistint(head);
+    free_dlistint(head);
+    head = NULL;
+    return (EXIT_SUCCESS);
+}

0x17-doubly_linked_lists/8-delete_dnodeint.c

@@ -0,0 +1,50 @@
+#include "lists.h"
+
+/**
+  * delete_dnodeint_at_index - Deletes the node at idx of a double linked list
+  * @head: header of double linked list
+  * @index: index of the node, starting from 0
+  * Return: 1 if it succeeded, -1 if it failed
+  */
+int delete_dnodeint_at_index(dlistint_t **head, unsigned int index)
+{
+	dlistint_t *pre, *headcopy = *head;
+	unsigned int i;
+
+	while (headcopy != NULL && headcopy->prev != NULL)
+	{
+		headcopy = headcopy->prev;
+		*head = (*head)->prev;
+	}
+	if (headcopy != NULL && index != 0)
+	{
+		for (i = 0; i < index && headcopy != NULL; i++)
+		{
+			pre = headcopy;
+			headcopy = headcopy->next;
+		}
+		if (headcopy != NULL)
+		{
+			pre->next = headcopy->next;
+			if (pre->next != NULL)
+				headcopy->next->prev = pre;
+			free(headcopy);
+			return (1);
+		}
+		return (-1);
+	}
+	if (headcopy != NULL && index == 0)
+	{
+		pre = headcopy->next;
+		if (pre == NULL)
+			*head = NULL;
+		else
+		{
+			pre->prev = NULL;
+			free(headcopy);
+			*head = pre;
+		}
+		return (1);
+	}
+	return (-1);
+}