octal | 易学教程

BigInteger Parse Octal String?

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问题 In Java, I could do //Parsing Octal String BigInteger b = new BigInteger("16304103460644701340432043410021040424210140423204",8); Then format it as I pleased b.toString(2); //2 for binary b.toString(10); //10 for decimal b.toString(16); //16 for hexadecimal C#'s BigInteger offers the formatting capabilities shown above but I can't seem to find a way to parse BIIIG (greater than 64 bit, unsigned) Octal values. 回答1: This may not be the most efficient solution, but if performance is not a

Strange behaviour with numbers that have a leading zero [duplicate]

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This question already has an answer here: php array behaving strangely with key value 07 & 08 5 answers Is this a bug in PHP? [duplicate] 8 answers I have some PHP code with some integers and all works fine, except when I have 08 or 0X as integer. It all works fine when I put them in quote. Example numbers: 2 //Works fine 08 //Doesn't work 012 //Doesn't work "08" //Works fine again "012" //Works fine again Can anyone tell me the reason behind it? If you simply write 08 and 09 (without quotes) or any other numeric with a leading 0, PHP believes you're writing an octal value, and 08 and 09 are

09 is not recognized where as 9 is recognized [duplicate]

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This question already has an answer here: Why is 08 not a valid integer literal in Java? 6 answers I am using quartz for schedulling. TriggerUtils.getDateOf(0,40,18,09,06); it accept 5 parameter. (seconds, minutes, hours, daysOfMonth, month). When i pass fourth parameter as "09". Eclipse give me error "The literal Octal 09 (digit 9) of type int is out of range ". But when i pass the fourth parameter as "9" instead of "09", it works. Can anyone explain me this error? James Van Huis In java, if you are defining an integer, a leading '0' will denote that you are defining a number in octal int i =

In what situations is octal base used?

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问题 I've seen binary and hex used quite often but never octal. Yet octal has it's own convention for being used in some languages (ie, a leading 0 indicating octal base). When is octal used? What are some typical situations when one would use octal or octal would be easier to reason about? Or is it merely a matter of taste? 回答1: Octal is used as a shorthand for representing file permissions on UNIX systems. For example, file mode rwxr-xr-x would be 0755 . 回答2: Octal is used when the number of

Why are leading zeroes used to represent octal numbers?

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问题 I've always wondered why leading zeroes ( 0 ) are used to represent octal numbers, instead of — for example — 0o . The use of 0o would be just as helpful, but would not cause as many problems as leading 0 es (e.g. parseInt('08'); in JavaScript). What are the reason(s) behind this design choice? 回答1: All modern languages import this convention from C, which imported it from B, which imported it from BCPL. Except BCPL used #1234 for octal and #x1234 for hexadecimal. B has departed from this

Why are Octal numeric literals not allowed in strict mode (and what is the workaround?)

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问题 Why are Octal numeric literals not allowed in JavaScript strict mode? What is the harm? "use strict"; var x = 010; //Uncaught SyntaxError: Octal literals are not allowed in strict mode. <h1>Check browser console for errors</h1> In case a developer needs to use Octals (which can mistakenly change a numbers meaning), is there a workaround? 回答1: The "why" part of the question is not really answerable. As for "how", off the top of my head... "use strict"; var x = parseInt('010', 8); document

Java int division confusing me

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问题 I am doing very simple int division and I am getting odd results. This code prints 2 as expected: public static void main(String[] args) { int i = 200; int hundNum = i / 100; System.out.println(hundNum); } This code prints 1 as not expected: public static void main(String[] args) { int i = 0200; int hundNum = i / 100; System.out.println(hundNum); } What is going on here? (Windows XP Pro, Java 1.6 running in Eclipse 3.4.1) 回答1: The value 0200 is an octal (base 8) constant. It is equal to 128

Python: Invalid Token

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Some of you may recognize this as Project Euler's problem number 11. The one with the grid. I'm trying to replicate the grid in a large multidimensional array, But it's giving me a syntax error and i'm not sure why grid = [ [ 08, 02, 22, 97, 38, 15, 00, 40, 00, 75, 04, 05, 07, 78, 52, 12, 50, 77, 91, 08 ], [ 49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 04, 56, 62, 00 ], [ 81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 03, 49, 13, 36, 65 ], ... And I get this error: File "D:\development\Python\ProjectEuler\p11.py", line 3 [ 08, 02, 22, 97, 38, 15, 00, 40, 00, 75,

printf with “%d” of numbers starting with 0 (ex “0102”) giving unexpected answer (ex '“66”)

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问题 I used below code in my printf statement. void main() { int n=0102; printf(\"%d\", n); } This prints 66 as the answer. I also changed the value of variable n to 012. It gives the answer 10. Please help me regarding how this conversion is done??? 回答1: This is because when the first digit of a number (integer constant) is 0 (and second must not be x or X ), the compiler interprets it as an octal number. Printing it with %d will give you a decimal value. To print octal value you should use %o

Is 0 a decimal literal or an octal literal?

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Zero is always zero, so it doesn't matter. But in a recent discussion with my friend he said that octal literals are almost unused today. Then it dawned upon me that actually almost all integer literals in my code are octal, namely 0 . Is 0 an octal literal according to the C++ grammar? What does the standard say? Yes, 0 is an Octal literal in C++. As per the C++ Standard: 2.14.2 Integer literals [lex.icon] integer-literal: decimal-literal integer-suffixopt octal-literal integer-suffixopt hexadecimal-literal integer-suffixopt decimal-literal: nonzero-digit decimal-literal digit octal-literal: