Output

To do I/O we need
```
#include <iostream>
```
cout is
- A variable name
- A special variable name
- the interface to the output stream.
<<
- Is called the stream insertion operator
- also called put to
- puts the thing on the right into the thing on the left
- Takes a stream operator and an expression
- converts the expression to a string of characters and inserts them into the output stream.
- This returns a stream operator.
- Notice, severial of these can be used at a time.
endl
- Adds the end of line marker into the output stream
- Also flushes the buffer, but don't worry about that yet.

  cout << "Hello";
  cout << "Hello " << "There ";
  cout << LastName << ", " << FirstName << endl;
  cout << LastName +  ", " +  FirstName << endl;