c++内存布局

using namespace std;

class Point3d
{
	public:
		Point3d( float x=0.0, float y=0.0, float z=0.0)
			: _x(x), _y(y), _z(z) {  }

		float *x_addr() { return &_x; }
		float *y_addr() { return &_y; }
		float *z_addr() { return &_z; }

		float x() { return _x; }
		float y() { return _y; }
		float z() { return _z; }

		void x( float xval ) { _x = xval; }
		void y( float yval ) { _y = yval; }
		void z( float zval ) { _z = zval; }

		void Point3d_print() {
			printf ("点坐标：(%g, %g, %g)\n", _x, _y, _z);
		}

	private:
		float _x;
		float _y;
		float _z;
};

int main()
{
	cout << "sizeof(Point3d) = " << sizeof(Point3d) << endl << endl;

	//C++中可以直接声明一个类对象
	Point3d pt(1, 2, 3);
	pt.Point3d_print();
	cout << "pt的内存大小：" << sizeof(pt) << endl;
	cout << "pt._x成员的值" << pt.x() << "，地址：" << pt.x_addr() << endl;
	cout << "pt._y成员的值" << pt.y() << "，地址：" << pt.y_addr() << endl;
	cout << "pt._z成员的值" << pt.z() << "，地址：" << pt.z_addr() << endl << endl;

	//也可以动态根据类指针在运行时申请内存创建一个对象
	Point3d *_pt = new Point3d(4, 5, 6);
	_pt->Point3d_print();
	cout << "_pt指向的对象的内存大小：" << sizeof(*_pt) << endl;
	cout << "_pt._x成员的值" << pt.x() << "，地址：" << pt.x_addr() << endl;
	cout << "_pt._y成员的值" << pt.y() << "，地址：" << pt.y_addr() << endl;
	cout << "_pt._z成员的值" << pt.z() << "，地址：" << pt.z_addr() << endl << endl;
	delete _pt;

	system("pause");
	return 0;
}