Java 8 IntStream Examples

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In Java, `IntStream` is a part of the java.util.stream package and represents a stream of primitive integers. It's designed to work with the functional programming features introduced in Java 8, allowing you to perform aggregate operations on sequences of elements. Here are some examples of using `IntStream`:

Example 1: Creating IntStream

import java.util.stream.IntStream;

public class IntStreamExample {

    public static void main(String[] args) {

        // Create an IntStream using range

        IntStream.range(1, 6).forEach(System.out::println); // Prints 1, 2, 3, 4, 5

        

        // Create an IntStream using rangeClosed

        IntStream.rangeClosed(1, 5).forEach(System.out::println); // Prints 1, 2, 3, 4, 5

    }

}

Example 2: Operations on IntStream

import java.util.stream.IntStream;

public class IntStreamExample {

    public static void main(String[] args) {

        // Sum of elements

        int sum = IntStream.range(1, 6).sum(); // sum = 15

        

        // Find the maximum element

        int max = IntStream.of(3, 1, 4, 1, 5, 9, 2, 6).max().orElse(0); // max = 9

        

        // Filter and print even numbers

        IntStream.range(1, 6)

                 .filter(n -> n % 2 == 0)

                 .forEach(System.out::println); // Prints 2, 4

    }

}

Example 3: Mapping with IntStream

import java.util.stream.IntStream;

public class IntStreamExample {

    public static void main(String[] args) {

        // Map each element to its square

        IntStream.range(1, 6)

                 .map(n -> n * n)

                 .forEach(System.out::println); // Prints 1, 4, 9, 16, 25

    }

}

Example 4: IntStream to Array

import java.util.stream.IntStream;

public class IntStreamExample {

    public static void main(String[] args) {

        // Convert IntStream to array

        int[] array = IntStream.range(1, 6).toArray(); // array = {1, 2, 3, 4, 5}

    }

}

Example 5: IntStream with Reduction

import java.util.stream.IntStream;

public class IntStreamExample {

    public static void main(String[] args) {

        // Use reduce to get the product of elements

        int product = IntStream.range(1, 6)

                               .reduce((x, y) -> x * y)

                               .orElse(1); // product = 120

    }

}

These examples cover a range of basic operations that you can perform using `IntStream` in Java. Remember that `IntStream` is part of the broader Java Stream API, and similar operations can be performed on streams of other types (e.g., `DoubleStream`, `LongStream`).

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