Are there binary literals in Java?

问题:

I want to declare my integer number by a binary literal. Is it possible in Java?

回答1:

Look at this link:

http://en.wikibooks.org/wiki/Java_Programming/Literals/Numeric_Literals/Integer_Literals

In Java, you may enter integer numbers in several formats:

1) As decimal numbers such as 1995, 51966. Negative decimal numbers such as -42 are actually expressions consisting of the integer literal with the unary negation operation.

2) As octal numbers, using a leading 0 (zero) digit and one or more additional octal digits (digits between 0 and 7), such as 077. Octal numbers may evaluate to negative numbers; for example 037777777770 is actually the decimal value -8.

3) As hexadecimal numbers, using the form 0x (or 0X) followed by one or more hexadecimal digits (digits from 0 to 9, a to f or A to F). For example, 0xCAFEBABEL is the long integer 3405691582. Like octal numbers, hexadecimal literals may represent negative numbers.

4) Starting in J2SE 7.0, as binary numbers, using the form 0b (or 0B) followed by one or more binary digits (0 or 1). For example, 0b101010 is the integer 42. Like octal and hex numbers, binary literals may represent negative numbers.

If you do not have J2SE 7.0 use this:

int val = Integer.parseInt("001101", 2); 

回答2:

In JDK 7 it is possible:

int binaryInt = 0b101; 

Just prefix your number with 0b.

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