Java™ How To Program (Early Objects), Tenth Edition

17.3.2 Terminal Operations count, min, max, sum and average

Class IntStream provides various terminal operations for common stream reductions on streams of int values. Terminal operations are eager—they immediately process the items in the stream. Common reduction operations for IntStreams include:

• count (line 19) returns the number of elements in the stream.

• min (line 21) returns the smallest int in the stream.

• max (line 23) returns the largest int in the stream.

• sum (line 24) returns the sum of all the ints in the stream.

• average (line 26) returns an OptionalDouble (package java.util) containing the average of the ints in the stream as a value of type double. For any stream, it’s possible that there are no elements in the stream. ...