The Great Nebula in Orion is a colorful place. Visible to the unaided eye, it appears as a small fuzzy patch in the constellation of Orion. Long exposure, digitally sharpened images like this, however, show the Orion Nebula to be a busy neighborhood of young stars, hot gas, and dark dust. The power behind much of the Orion Nebula (M42) is the Trapezium - four of the brightest stars in the nebula. Many of the filamentary structures visible are actually shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula spans about 40 light years and is located about 1500 light years away in the same spiral arm of our Galaxy as the Sun.
Image credit: Stefan Seip
… C++ offers even more flexible control over the visibility of member
objects and member functions. Specifically, members may be placed in the
public, private, or protected parts of a class. Members declared in the
public parts are visible to all clients; members declared in the private
parts are fully encapsulated; and members declared in the protected parts
are visible only to the class itself and its subclasses. C++ also supports
the notion of *_______friends*: cooperative classes that are permitted to see each
other’s private parts.
— Grady Booch, “Object Oriented Design with Applications”