DSA Project – Library Book Management System

Program 1

// Project Library Books Management System using doubly linked list
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct Book {
    int id;
    char title[100];
    char author[100];
    struct Book *prev;
    struct Book *next;
};

struct Book *head = NULL;

// Function to create a new book node
struct Book* createBook(int id, const char* title, const char* author)
 {
    struct Book* newBook = (struct Book*)malloc(sizeof(struct Book));
    newBook->id = id;
    strcpy(newBook->title, title);
    strcpy(newBook->author, author);
    newBook->prev = NULL;
    newBook->next = NULL;
    return newBook;
}

// Add book to the end of the list
void addBook(int id, const char* title, const char* author) {
    struct Book* newBook = createBook(id, title, author);
    if (head == NULL) {
        head = newBook;
        return;
    }

    struct Book* temp = head;
    while (temp->next != NULL)
        temp = temp->next;

    temp->next = newBook;
    newBook->prev = temp;
    printf("Book added successfully.\n");
}

// Display all books
void displayBooks() {
    if (head == NULL) {
        printf("No books in the library.\n");
        return;
    }

    struct Book* temp = head;
    
    printf("\nBooks in Library:\n");
    printf("ID\tTitle\t\tAuthor\n");
    printf("\n---------------------------------------------\n");
    while (temp != NULL) {
        printf("%d\t%s\t\t%s\n", temp->id, temp->title, temp->author);
        temp = temp->next;
    }
    printf("\n--------------------------------------------");
}

// Search for a book by ID
void searchBook(int id) {
    struct Book* temp = head;
    while (temp != NULL) {
        if (temp->id == id) {
            printf("Book found:\n");
            printf("ID: %d\nTitle: %s\nAuthor: %s\n", temp->id, temp->title, temp->author);
            return;
        }
        temp = temp->next;
    }
    printf("Book with ID %d not found.\n", id);
}

// Delete a book by ID
void deleteBook(int id) {
    struct Book* temp = head;

    while (temp != NULL && temp->id != id)
        temp = temp->next;

    if (temp == NULL) 
    {
        printf("Book not found.\n");
        return;
    }
    int choice;
    printf("ID: %d\nTitle: %s\nAuthor: %s\n", temp->id, temp->title, temp->author);
    printf("\n Are you sure want to delete(1-Yes): ");
    scanf("%d",&choice);
  if(choice==1)  
 { 
    if (temp->prev != NULL)
        temp->prev->next = temp->next;
    else
        head = temp->next; // deleting head

    if (temp->next != NULL)
        temp->next->prev = temp->prev;

    free(temp);
    printf("Book deleted successfully.\n");
 }   
}

// Main menu
int main() {
    int choice, id;
    char title[100], author[100];

    while (1) {
        printf("\n===== Library Menu =====\n");
        printf("1. Add Book\n");
        printf("2. Delete Book\n");
        printf("3. Display All Books\n");
        printf("4. Search Book by ID\n");
        printf("5. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        getchar(); // to consume newline

        switch (choice) {
            case 1:
                printf("Enter Book ID: ");
                scanf("%d", &id);
                getchar();
                printf("Enter Book Title: ");
                fgets(title, sizeof(title), stdin);
                title[strcspn(title, "\n")] = '\0'; // remove newline   // gets(title)
                printf("Enter Book Author: ");
                fgets(author, sizeof(author), stdin);
                author[strcspn(author, "\n")] = '\0';
                addBook(id, title, author);
                break;

            case 2:
                printf("Enter Book ID to delete: ");
                scanf("%d", &id);
                deleteBook(id);
                break;

            case 3:
                displayBooks();
                break;

            case 4:
                printf("Enter Book ID to search: ");
                scanf("%d", &id);
                searchBook(id);
                break;

            case 5:
                printf("Exiting program.\n");
                exit(0);

            default:
                printf("Invalid choice. Try again.\n");
        }
    }

    return 0;
}