I am getting Nullpointerexception in java when I pass an method in array for taking many inputs of that method

Question

{ books obj = new books();

        int n;
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the number of books details you want to enter");

// inputting n = sc.nextInt();

        books  array[]  = new books[n];


            for (int i = 0; i<=n; i++) 
            {
             array[i].input();
            }

}