C++ struct as class

#include <iostream>

struct test {
	int a;

	int a_square();
};

int test::a_square()
{
	return a*a;
}

int main()
{
	struct test A;
	A.a = 123;

	std::cout << A.a << std::endl;
	std::cout << A.a_square() << std::endl;

	getchar();
	
	return 0;
}