The document discusses user input of strings in C++. It notes that while cin can be used to extract user input as a string, it will only read a single word due to treating whitespace as a terminating character. To read an entire line of text from the user, including multiple words, the getline() function should be used instead, taking cin as the first parameter and the string variable as the second parameter.

1. C++User Input
String
Rai Masamune

2. User Input
Strings
 It is possible to use the extraction operator >> on cin
to display a string entered by a user:

3. User Input
Strings
However, cin considers a space (whitespace, tabs, etc) as a
terminating character,
which means that it can only display a single word (even if you
type many words):

4. User Input
String
 From the example above, you would expect the
program to print "John Doe", but it only prints "John".
 That's why, when working with strings, we often use
the getline() function to read a line of text. It takes
cin as the first parameter, and the string variable as
the second:

5. User Input
String