#include <iostream>
#include <cstdlib>

//Introducing two more members of namespace std, cin and cerr.
//And another possible exit status number, EXIT_FAILURE.
//
//The if (!std::cin) means "if std::cin is in an unhealthy state as a result
//of a failure of the previous attempt at input".

int main()
{
	int price {0};   //This variable will die whenever we return.

	std::cout << "Please type the price and press RETURN.\n";
	std::cin >> price;

	if (!std::cin) {
		std::cerr << "Sorry, that wasn't an acceptable number.\n";
		return EXIT_FAILURE;
	}
						  
	std::cout << "The variable contains " << price << ".\n";
	return EXIT_SUCCESS;
}