Write a C program that uses structures to represent details of five books (title, author, publisher and price) and prints them out. [8] OR Discuss the concept of binary file handling in C…

Model Answer for NEB 2081 (Class 12, Computer Science)

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Part 1: C Program to Store and Print Book Details Using Structures

#include <stdio.h>
#include <string.h>

```figure
{"type":"array","values":[{"label":"Book 1","fields":{"title":"The C Programming Language","author":"K&R","publisher":"Prentice Hall","price":1200}},{"label":"Book 2","fields":{"title":"Data Structures","author":"Horstmann","publisher":"Pearson","price":1500}},{"label":"Book 3","fields":{"title":"Operating Systems","author":"Silberschatz","publisher":"Wiley","price":1800}},{"label":"Book 4","fields":{"title":"Computer Networks","author":"Forouzan","publisher":"McGraw-Hill","price":1600}},{"label":"Book 5","fields":{"title":"Algorithms","author":"Cormen","publisher":"MIT Press","price":2000}}],"caption":"Structure array representation of 5 books (as used in the program)"}

// Define a structure to store book details struct Book { char title[50]; char author[50]; char publisher[50]; float price; };

int main() { // Declare an array of 5 Book structures struct Book books[5];

// Input details for 5 books
for (int i = 0; i < 5; i++) {
    printf("\nEnter details for Book %d:\n", i + 1);

    printf("Title: ");
    fgets(books[i].title, 50, stdin);
    books[i].title[strcspn(books[i].title, "\n")] = '\0'; // Remove newline

    printf("Author: ");
    fgets(books[i].author, 50, stdin);
    books[i].author[strcspn(books[i].author, "\n")] = '\0';

    printf("Publisher: ");
    fgets(books[i].publisher, 50, stdin);
    books[i].publisher[strcspn(books[i].publisher, "\n")] = '\0';

    printf("Price: ");
    scanf("%f", &books[i].price);
    while (getchar() != '\n'); // Clear input buffer
}

// Print the details of all books
printf("\n--- Book Details ---\n");
for (int i = 0; i < 5; i++) {
    printf("\nBook %d:\n", i + 1);
    printf("Title: %s\n", books[i].title);
    printf("Author: %s\n", books[i].author);
    printf("Publisher: %s\n", books[i].publisher);
    printf("Price: %.2f\n", books[i].price);
}

return 0;

}

How it works:

• A struct Book is defined to store title, author, publisher, and price of a book.
• An array of 5 such structures (books[5]) is declared to store details of 5 books.
• A loop takes input for each book using fgets() (to handle spaces in names) and scanf() (for price).
• Another loop prints the stored details in a structured format.

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Part 2: Binary File Handling in C (Alternative Answer)

Concept of Binary File Handling

Binary file handling in C involves reading/writing data in its raw binary format (not text) directly to/from a file. Unlike text files (where data is converted to ASCII/Unicode), binary files store data exactly as it is in memory, making them faster and more efficient for large datasets (e.g., images, databases, executable files).

Key advantages:

• Speed: No conversion overhead (faster I/O).
• Memory efficiency: Stores data compactly (e.g., integers as 4 bytes, not as text).
• Exact representation: Preserves data types (e.g., float, struct) without corruption.

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Role of putw() and getw()

These functions are used for binary I/O of integers (specifically int type) in C.

Limitations:

• Only works with int (not float, char, or structures).
• Deprecated in modern C (replaced by fwrite()/fread() for portability).

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Example: Storing and Retrieving Integers in Binary Mode

#include <stdio.h>

int main() {
    FILE *fp;
    int num, i;

    // Write integers to a binary file
    fp = fopen("numbers.bin", "wb"); // "wb" = write binary
    for (i = 1; i <= 5; i++) {
        num = i * 10;
        putw(num, fp); // Store each number in binary
    }
    fclose(fp);

    // Read integers from the binary file
    fp = fopen("numbers.bin", "rb"); // "rb" = read binary
    printf("Numbers read from binary file:\n");
    for (i = 0; i < 5; i++) {
        num = getw(fp); // Retrieve each number
        printf("%d ", num);
    }
    fclose(fp);

    return 0;
}

Output:

Numbers read from binary file:
10 20 30 40 50

Explanation:

1. Writing:
   • Opens "numbers.bin" in binary write mode ("wb").
   • Uses putw() to store integers 10, 20, ..., 50 directly in binary.
2. Reading:
   • Opens the same file in binary read mode ("rb").
   • Uses getw() to retrieve integers in the same order.

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Modern Alternative: fwrite() and fread()

For structures or non-integer data, use:

struct Book {
    char title[50];
    float price;
};

// Writing a structure to binary file
fwrite(&book, sizeof(struct Book), 1, fp);

// Reading a structure from binary file
fread(&book, sizeof(struct Book), 1, fp);

Why prefer fwrite()/fread()?

• Works with any data type (structures, arrays, floats).
• More portable across systems.
• Supports multiple records (e.g., fwrite(&books, sizeof(books), 5, fp) for 5 books).

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