【C++ Primer Plus习题】16.10

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问题:

解答:

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <memory>
using namespace std;

struct Review
{
	string title;
	int rating;
	int price;
};

bool operator<(const shared_ptr<Review>& p1, const shared_ptr<Review>& p2);
bool FillReview(Review& rr);
void ShowReview(const shared_ptr<Review>& p);
bool worseThan(const shared_ptr<Review>& p1, const shared_ptr<Review>& p2);
bool expenThan(const shared_ptr<Review>& p1, const shared_ptr<Review>& p2);


int main()
{
	vector<shared_ptr<Review>>books;
	Review temp;
	while (FillReview(temp))
	{
		shared_ptr<Review>pd(new Review(temp));
		books.push_back(pd);
	}
	if (books.size() > 0)
	{
		cout << "Choose the way to sort: "
			<< "r:rate, s: rate r, p:price, d:price, d:price r, q:quit\n";
		char choice;
		while (cin >> choice && choice != 'q')
		{
			switch (choice)
			{
			case 'r':sort(books.begin(), books.end(), worseThan);
				break;
			case 's':sort(books.rbegin(), books.rend(), worseThan);
				break;
			case 'p':sort(books.begin(), books.end(), expenThan);
				break;
			case 'd':sort(books.rbegin(), books.rend(), expenThan);
				break;
			default:
				break;
			}
			for_each(books.begin(), books.end(), ShowReview);
			cout<<"Please choose the way to sort: "
				<< "r:rate, s: rate r, p:price, d:price, d:price r, q:quit\n";
		}
		
	}

	return 0;
}


bool operator<(const shared_ptr<Review>& p1, const shared_ptr<Review>& p2)
{
	if (p1->title < p2->title)
		return true;
	else if (p1->title == p2->title && p1->rating < p2->rating)
		return true;
	else
		return false;
}
bool FillReview(Review& rr)
{
	cout << "Enter book title (quit to quit): ";
	getline(cin, rr.title);
	if (rr.title == "quit" || rr.title == "")
		return false;
	cout << "Enter book rating: ";
	cin >> rr.rating;
	if (!cin)
		return false;
	cout << "Enter book price: ";
	cin >> rr.price;
	if (!cin)
		return false;
	while (cin.get() != '\n')
	{
		continue;
	}
	return true;
}
void ShowReview(const shared_ptr<Review>& p)
{
	cout << p->rating << "\t" << p->title << "\t" << p->price << endl;
}
bool  worseThan(const shared_ptr<Review>& p1, const shared_ptr<Review>& p2)
{
	if (p1->rating < p2->rating)
		return true;
	else
		return false;
}
bool expenThan(const shared_ptr<Review>& p1, const shared_ptr<Review>& p2)
{
	if (p1->price < p2->price)
		return true;
	else
		return false;
}