CODEWITHSUNDEEP
javaintshort
St.Antario
St.Antario

Reputation: 27375

int to short with two most significant bytes

I have an integer

int a = //...

ints in java consist of 4 bytes. If we cast it to short, we will take two least significant bytes. What is the fastest way to get short consisting of 2 most significant bytes of the int?

short b = //take two most significant bytes of a

Upvotes: 1

Views: 619

Answers (2)

Sergey Vyacheslavovich Brunov
Sergey Vyacheslavovich Brunov

Reputation: 18106

It is sufficient to use the right bit shift operator (>>). Because the int primitive data type has the size of 32 bits (Primitive Data Types (The Java™ Tutorials > Learning the Java Language > Language Basics)) and you need to get the 16 most significant bits, it is necessary to perform the right bit shift by 16 bits:

public class Program {
    public static void main(final String[] args) {
        final int input = 0xABCDEFAB;
        final short output = (short) (input >> 16);
        System.out.printf("Original integer: %X%n", input);
        System.out.printf("Short with two most significant bytes: %X%n", output);
    }
}

Also, it is worth noting that the Java language has signed (<<, >>) and unsigned (<<<, >>>) bit shift operators. Please refer to the article: Bitwise and Bit Shift Operators (The Java™ Tutorials > Learning the Java Language > Language Basics).

The same result can be produced using the division operator:

public class Program {
    public static void main(final String[] args) {
        final int input = 0xABCDEFAB;
        final short output = (short) (input / 0x10000);
        System.out.printf("Original integer: %X%n", input);
        System.out.printf("Short with two most significant bytes: %X%n", output);
    }
}

Upvotes: 4

John Kugelman
John Kugelman

Reputation: 361585

short b = (short) (a >> 16);

Upvotes: 5

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