When a liquid fire extinguisher has a hose, the stream of liquid coming from the hose is called the "hose stream" and can be directed at the base of the flames.

A jet stream of water shot out of the hose.

The light will stream through the window in the morning. The water will stream through the hose.

A "Scotch Hose" is a 2" high pressure hose fitted with a regulation Spengler Nozzle, capable of providing a mist, spray, or stream of the finest quality scotch.

endl is not an operator. Is is a stream manipulator. It inserts and end-of-line into the stream.

cout << "This is a test" << endl << "This is also a test" << endl;

Gives you ...

This is a test

This is also a test