Nidhu's Problem

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

struct library {
    char name[200];
    int id;
    double price;
    char authorName[200];
    int publicationYear;
    char issueDate[200];
};

typedef struct library Library;

int main() {
    Library book[20];
    FILE *input = fopen("input.txt", "r+");
    FILE *output = fopen("output.txt", "a");
    FILE *authorWiseBook = fopen("author_wise_book.txt", "a");
    FILE *publicationYearFile = fopen("publication_yr_1991_2000_book.txt", "a");
    int i, inputSize = 3;
    for (i = 0; i < inputSize; i++) {
        fscanf(input, "%s", &book[i].name);
        fscanf(input, "%d %lf", &book[i].id, &book[i].price);
        fscanf(input, "%s", &book[i].authorName);
        fscanf(input, "%d", &book[i].publicationYear);
        fgets(book[i].issueDate, 100, input);
    }

    // write book info in output file
    for (i = 0; i < inputSize; i++) {
        fprintf(output, "%s %d %.2lf %s %d %s\n", book[i].name, book[i].id, book[i].price, book[i].authorName, book[i].publicationYear, book[i].issueDate);
    }

    double max = 0, min = 0;
    int index = 0;
    for (i = 0; i < inputSize; i++) {
        if (book[i].price > max) {
            max = book[i].price;
            index = i;
        }
    }

    // printing height price book info in console
    printf("Height price book info:\n");
    printf("%s %d %.2lf %s %d %s\n", book[index].name, book[index].id, book[index].price, book[index].authorName, book[index].publicationYear, book[index].issueDate);

    index = 0;
    for (i = 0; i < inputSize; i++) {
        if (book[i].price < min) {
            min = book[i].price;
            index = i;
        }
    }

    // printing lowest price book info in console
    printf("Lowest price book info:\n");
    printf("%s %d %.2lf %s %d %s\n", book[index].name, book[index].id, book[index].price, book[index].authorName, book[index].publicationYear, book[index].issueDate);

    char userInput[200];
    printf("Enter a author name for search:\n");
    scanf("%s", &userInput);

    index = -1;
    for (i = 0; i < inputSize; i++) {
        if (strcmp(book[i].authorName, userInput) == 0) {
            index = i;
            break;
        }
    }

    // Author wise book
    if (index == -1) {
        printf("Author is not in the list\n");
    } else {
        fprintf(authorWiseBook, "%s %d %.2lf %s %d %s", book[index].name, book[index].id, book[index].price, book[index].authorName, book[index].publicationYear, book[index].issueDate);
    }

    // Publication year wise book
    for (i = 0; i < inputSize; i++) {
        if(book[i].publicationYear >= 1991 && book[i].publicationYear <= 2000) {
            fprintf(publicationYearFile, "%s %d %.2lf %s %d %s\n", book[i].name, book[i].id, book[i].price, book[i].authorName, book[i].publicationYear, book[i].issueDate);
        }
    }

    // Take input from user
    printf("Enter more two book information: \n");
    for (i = 0; i < 2; i++) {
        printf("Enter book Name: ");
        fflush(stdin);
        scanf("%s", &book[i].name);
        fflush(stdout);
        printf("Enter book id: ");
        scanf("%d", &book[i].id);
        printf("Enter book price: ");
        scanf("%lf", &book[i].price);
        printf("Enter book author name: ");
        scanf("%s", &book[i].authorName);
        printf("Enter publication year: ");
        scanf("%d", &book[i].publicationYear);
        printf("Enter issue date: ");
        fflush(stdin);
        gets(book[i].issueDate);
        fflush(stdout);
    }

    // Append the infromation in input file
    for (i = 0; i < 2; i++) {
        fprintf(input, "%s %d %.2lf %s %d %s\n", book[i].name, book[i].id, book[i].price, book[i].authorName, book[i].publicationYear, book[i].issueDate);
    }

    fclose(input);
    fclose(output);
    fclose(authorWiseBook);
    fclose(publicationYearFile);
}