#include <iostream>
#include <cstdlib>
#include <string>
using namespace std;

struct Book {
	string title;
	string author;
	int pages;
	float hoursToRead;
};

void estimateReadingTime(Book *p, float readingSpeed);  // Function declaration

int main()
{
	Book myBook {"Oliver Twist", "Charles Dickens", 608, 0.0};
	float speed = 40.0;  // Pages per hour

	estimateReadingTime(&myBook, speed);  // Pass address of the book to the function

	return EXIT_SUCCESS;
}

void estimateReadingTime(Book *p, float readingSpeed)
{
	if (readingSpeed <= 0) {
		cout << "Invalid reading speed.\n";
		return;
	}

	p->hoursToRead = p->pages / readingSpeed;

	cout << "At " << readingSpeed << " pages per hour, it will take about "
		<< p->hoursToRead << " hours to read \"" << p->title
		<< "\" by " << p->author << ".\n";
}