Feat/Sorting a singly linked list using C language

data_structures/circular_linked_list.c

@@ -0,0 +1,222 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+struct node {
+    int data;
+    struct node* next;
+} *head = NULL, *temp = NULL, *newnode = NULL;
+
+// Create a new node
+struct node* create_node() {
+    newnode = (struct node*)malloc(sizeof(struct node));
+    printf("\nEnter the data: ");
+    scanf("%d", &newnode->data);
+    newnode->next = NULL;
+    return newnode;
+}
+
+// Count nodes in the circular linked list
+int count() {
+    int cnt = 0;
+    if (head == NULL) return 0;
+
+    temp = head;
+    do {
+        cnt++;
+        temp = temp->next;
+    } while (temp != head);
+
+    return cnt;
+}
+
+// Insert at beginning
+void ins_begin() {
+    newnode = create_node();
+    if (head == NULL) {
+        head = newnode;
+        newnode->next = head;
+    } else {
+        temp = head;
+        while (temp->next != head) temp = temp->next;
+        newnode->next = head;
+        head = newnode;
+        temp->next = head;
+    }
+    printf("\n%d is inserted at beginning\n", newnode->data);
+}
+
+// Insert at given position
+void ins_pos(int pos) {
+    if (pos < 1 || pos > count() + 1) {
+        printf("\nInvalid position\n");
+        return;
+    }
+
+    if (pos == 1) {
+        ins_begin();
+        return;
+    }
+
+    newnode = create_node();
+    temp = head;
+    for (int i = 1; i < pos - 1; i++) temp = temp->next;
+
+    newnode->next = temp->next;
+    temp->next = newnode;
+    printf("\n%d is inserted at position %d\n", newnode->data, pos);
+}
+
+// Insert at end
+void ins_end() {
+    newnode = create_node();
+    if (head == NULL) {
+        head = newnode;
+        newnode->next = head;
+    } else {
+        temp = head;
+        while (temp->next != head) temp = temp->next;
+        temp->next = newnode;
+        newnode->next = head;
+    }
+    printf("\n%d is inserted at end\n", newnode->data);
+}
+
+// Delete from beginning
+void del_beg() {
+    if (head == NULL) {
+        printf("\nEmpty list\n");
+        return;
+    }
+
+    struct node* to_delete = head;
+    if (head->next == head) {
+        printf("\n%d is deleted\n", head->data);
+        free(head);
+        head = NULL;
+        return;
+    }
+
+    temp = head;
+    while (temp->next != head) temp = temp->next;
+    head = head->next;
+    temp->next = head;
+
+    printf("\n%d is deleted\n", to_delete->data);
+    free(to_delete);
+}
+
+// Delete from a position
+void del_pos(int pos) {
+    if (head == NULL) {
+        printf("\nEmpty list\n");
+        return;
+    }
+    int total = count();
+    if (pos < 1 || pos > total) {
+        printf("\nInvalid position\n");
+        return;
+    }
+
+    if (pos == 1) {
+        del_beg();
+        return;
+    }
+
+    temp = head;
+    for (int i = 1; i < pos - 1; i++) temp = temp->next;
+
+    struct node* to_delete = temp->next;
+    temp->next = to_delete->next;
+
+    printf("\n%d is deleted\n", to_delete->data);
+    free(to_delete);
+}
+
+// Delete from end
+void del_end() {
+    if (head == NULL) {
+        printf("\nEmpty list\n");
+        return;
+    }
+
+    if (head->next == head) {
+        printf("\n%d is deleted\n", head->data);
+        free(head);
+        head = NULL;
+        return;
+    }
+
+    temp = head;
+    while (temp->next->next != head) temp = temp->next;
+
+    struct node* to_delete = temp->next;
+    temp->next = head;
+
+    printf("\n%d is deleted\n", to_delete->data);
+    free(to_delete);
+}
+
+// Display the list
+void display() {
+    if (head == NULL) {
+        printf("\nEmpty list\n");
+        return;
+    }
+    temp = head;
+    do {
+        printf("%d -> ", temp->data);
+        temp = temp->next;
+    } while (temp != head);
+    printf("(head)\n");
+}
+
+// Main menu
+int main() {
+    int n;
+    while (1) {
+        printf("\nSELECT OPERATION\n");
+        printf("1. Insertion\n2. Deletion\n3. Display\n4. Exit\nEnter your choice: ");
+        scanf("%d", &n);
+
+        switch (n) {
+            case 1: {
+                int x, pos;
+                printf("SELECT INSERTION TYPE:\n1. Insert at beginning\n2. Insert at position\n3. Insert at end\nEnter your choice: ");
+                scanf("%d", &x);
+
+                switch (x) {
+                    case 1: ins_begin(); break;
+                    case 2: 
+                        printf("Enter the position to insert node: ");
+                        scanf("%d", &pos);
+                        ins_pos(pos);
+                        break;
+                    case 3: ins_end(); break;
+                    default: printf("\nInvalid choice for insertion!\n");
+                }
+                break;
+            }
+            case 2: {
+                int z, pos;
+                printf("SELECT DELETION TYPE:\n1. Delete from beginning\n2. Delete from position\n3. Delete from end\nEnter your choice: ");
+                scanf("%d", &z);
+
+                switch (z) {
+                    case 1: del_beg(); break;
+                    case 2: 
+                        printf("Enter the position to delete node: ");
+                        scanf("%d", &pos);
+                        del_pos(pos);
+                        break;
+                    case 3: del_end(); break;
+                    default: printf("\nInvalid choice for deletion!\n");
+                }
+                break;
+            }
+            case 3: display(); break;
+            case 4: printf("\nExiting\n"); exit(0);
+            default: printf("\nInvalid choice\n");
+        }
+    }
+    return 0;
+}

data_structures/doubly_linked_list.c

@@ -0,0 +1,32 @@
+void ins_pos() {
+    int pos;
+    printf("\nEnter the position where the node should be inserted: ");
+    scanf("%d", &pos);
+
+    if (pos < 1 || pos > count() + 1) {
+        printf("\nInvalid position!\n");
+        return;
+    }
+
+    if (pos == 1) {
+        ins_beg();
+        return;
+    }
+
+    struct node *newnode = create_node();  // <<< ADD THIS LINE
+
+    temp = head;
+    for (int i = 1; i < pos - 1; i++) {
+        temp = temp->next;
+    }
+
+    newnode->next = temp->next;
+    newnode->prev = temp;
+
+    if (temp->next != NULL) {
+        temp->next->prev = newnode;
+    }
+
+    temp->next = newnode;
+    printf("\n%d is inserted at position %d\n", newnode->data, pos);
+}