#include <iostream>

int main()
{
	const int a = 20;
	int *b;
	//b = &a;
	std::cout << &a << std::endl;
	std::cout << b << std::endl;
	b = const_cast<int*>(&a);
	*b = 30;
	std::cout << &a << std::endl;
	std::cout << a << std::endl;
	std::cout << b << std::endl;
	std::cout << *b << std::endl;
}