Created doubly-linked-list

doubly-linked-list

@@ -0,0 +1,237 @@
+/* Implementation of doubly linked list */
+#include <stdio.h>
+#include <stdlib.h>
+
+struct node {
+    struct node *prev;
+    struct node *next;
+    int data;
+};
+
+struct node *head;
+
+void insertion_beginning();
+void insertion_last();
+void insertion_specified();
+void deletion_beginning();
+void deletion_last();
+void deletion_specified();
+void display();
+void search();
+
+void main() {
+    int choice = 0;
+    while (choice != 9) {
+        printf("\n*********Main Menu*********\n");
+        printf("\nChoose one option from the following list ...\n");
+        printf("\n===============================================\n");
+        printf("\n1.Insert in beginning\n2.Insert at last\n3.Insert at any random location\n4.Delete from Beginning\n5.Delete from last\n6.Delete the node after the given data\n7.Search\n8.Show\n9.Exit\n");
+        printf("\nEnter your choice?\n");
+        scanf("\n%d", &choice);
+        switch (choice) {
+            case 1:
+                insertion_beginning();
+                break;
+            case 2:
+                insertion_last();
+                break;
+            case 3:
+                insertion_specified();
+                break;
+            case 4:
+                deletion_beginning();
+                break;
+            case 5:
+                deletion_last();
+                break;
+            case 6:
+                deletion_specified();
+                break;
+            case 7:
+                search();
+                break;
+            case 8:
+                display();
+                break;
+            case 9:
+                exit(0);
+                break;
+            default:
+                printf("Please enter valid choice..");
+        }
+    }
+}
+
+void insertion_beginning() {
+    struct node *ptr;
+    int item;
+    ptr = (struct node *)malloc(sizeof(struct node));
+    if (ptr == NULL) {
+        printf("\nOVERFLOW");
+    } else {
+        printf("\nEnter Item value");
+        scanf("%d", &item);
+
+        if (head == NULL) {
+            ptr->next = NULL;
+            ptr->prev = NULL;
+            ptr->data = item;
+            head = ptr;
+        } else {
+            ptr->data = item;
+            ptr->prev = NULL;
+            ptr->next = head;
+            head->prev = ptr;
+            head = ptr;
+        }
+        printf("\nNode inserted\n");
+    }
+}
+
+void insertion_last() {
+    struct node *ptr, *temp;
+    int item;
+    ptr = (struct node *)malloc(sizeof(struct node));
+    if (ptr == NULL) {
+        printf("\nOVERFLOW");
+    } else {
+        printf("\nEnter value");
+        scanf("%d", &item);
+        ptr->data = item;
+        if (head == NULL) {
+            ptr->next = NULL;
+            ptr->prev = NULL;
+            head = ptr;
+        } else {
+            temp = head;
+            while (temp->next != NULL) {
+                temp = temp->next;
+            }
+            temp->next = ptr;
+            ptr->prev = temp;
+            ptr->next = NULL;
+        }
+        printf("\nnode inserted\n");
+    }
+}
+
+void insertion_specified() {
+    struct node *ptr, *temp;
+    int item, loc, i;
+    ptr = (struct node *)malloc(sizeof(struct node));
+    if (ptr == NULL) {
+        printf("\n OVERFLOW");
+    } else {
+        temp = head;
+        printf("Enter the location");
+        scanf("%d", &loc);
+        for (i = 0; i < loc; i++) {
+            temp = temp->next;
+            if (temp == NULL) {
+                printf("\n There are less than %d elements", loc);
+                return;
+            }
+        }
+        printf("Enter value");
+        scanf("%d", &item);
+        ptr->data = item;
+        ptr->next = temp->next;
+        ptr->prev = temp;
+        temp->next = ptr;
+        temp->next->prev = ptr;
+        printf("\nnode inserted\n");
+    }
+}
+
+void deletion_beginning() {
+    struct node *ptr;
+    if (head == NULL) {
+        printf("\n UNDERFLOW");
+    } else if (head->next == NULL) {
+        head = NULL;
+        free(head);
+        printf("\nnode deleted\n");
+    } else {
+        ptr = head;
+        head = head->next;
+        head->prev = NULL;
+        free(ptr);
+        printf("\nnode deleted\n");
+    }
+}
+
+void deletion_last() {
+    struct node *ptr;
+    if (head == NULL) {
+        printf("\n UNDERFLOW");
+    } else if (head->next == NULL) {
+        head = NULL;
+        free(head);
+        printf("\nnode deleted\n");
+    } else {
+        ptr = head;
+        if (ptr->next != NULL) {
+            ptr = ptr->next;
+        }
+        ptr->prev->next = NULL;
+        free(ptr);
+        printf("\nnode deleted\n");
+    }
+}
+
+void deletion_specified() {
+    struct node *ptr, *temp;
+    int val;
+    printf("\n Enter the data after which the node is to be deleted : ");
+    scanf("%d", &val);
+    ptr = head;
+    while (ptr->data != val)
+        ptr = ptr->next;
+    if (ptr->next == NULL) {
+        printf("\nCan't delete\n");
+    } else if (ptr->next->next == NULL) {
+        ptr->next = NULL;
+    } else {
+        temp = ptr->next;
+        ptr->next = temp->next;
+        temp->next->prev = ptr;
+        free(temp);
+        printf("\nnode deleted\n");
+    }
+}
+
+void display() {
+    struct node *ptr;
+    printf("\n printing values...\n");
+    ptr = head;
+    while (ptr != NULL) {
+        printf("%d\n", ptr->data);
+        ptr = ptr->next;
+    }
+}
+
+void search() {
+    struct node *ptr;
+    int item, i = 0, flag;
+    ptr = head;
+    if (ptr == NULL) {
+        printf("\nEmpty List\n");
+    } else {
+        printf("\nEnter item which you want to search?\n");
+        scanf("%d", &item);
+        while (ptr != NULL) {
+            if (ptr->data == item) {
+                printf("\nitem found at location %d ", i + 1);
+                flag = 0;
+                break;
+            } else {
+                flag = 1;
+            }
+            i++;
+            ptr = ptr->next;
+        }
+        if (flag == 1) {
+            printf("\nItem not found\n");
+        }
+    }
+}