In Java and several other languages, an integer literal beginning with `0` is interpreted as an octal (base 8) quantity.

For single-digit numbers (other than `08` and `09`, which are not allowed), the result is the same, so you might not notice that they are being interpreted as octal. However, if you write numbers with more than one significant digit you might be confused by the result.

For example:

    010 ==  8
    024 == 20

Since octal literals are usually not what you want, you should always take care to never begin an integer literal with `0`, unless of course you are actually trying to write zero by itself.

Any number prefixed with a 0 is considered octal. Octal numbers can only use digits 0-7, just like decimal can use 0-9, and binary can use 0-1.

    // octal to decimal
    01  // 1
    02  // 2
    07  // 7
    010 // 8
    020 // 16

    // octal to binary (excluding most significant bit)
    01  // 1 
    02  // 10
    07  // 111
    010 // 1000 
    020 // 10000

&gt; There are 10 types of people, those who understand ternary, those who don&#39;t, and those who think this is a stupid joke.

From the [Java specification][1]:

&gt; An octal numeral consists of an ASCII digit 0 followed by one or more of the ASCII digits 0 through 7 and can represent a positive, zero, or negative integer.


  [1]: http://java.sun.com/docs/books/jls/second_edition/html/lexical.doc.html

Leading zero means the value is in octal. 8 is not an octal digit, no more than 2 is valid in binary or G is valid in hexadecimal.

In **Java**, if you are defining an int with a leading &#39;0&#39; denotes that you are defining a number in **Octal**.

int **a = 08** is giving out of range error because there is no any number &#39;8&#39; in **Octal**. **Octal** provides 0-7 numbers only.

If you define **a = 07** then it&#39;s not giving out of range error because the numbers &#39;0&#39; and &#39;7&#39; are within the Octal&#39;s range.  

In most of programming language like `Java` and `C/C++`, the number with leading zero are interpreted as [octal number][1]. As we know octal numbers are only represented within `0` to `7` digits only. Hence numbers like `05`,`03`,`054` are valid but the numbers like `078`,`0348`,`09`,`08` are tends to invalid.


  [1]: https://en.wikipedia.org/wiki/Octal

I have an ImageButton which is disabled (non clickable or set as disabled). I want to give an UI feel to the user that it is disabled without using any other image.

Is there any way to do this?

Android ImageButton with disabled UI feel

Let us suppose I have this markup

    &lt;h3 id=&quot;first&quot;&gt;First&lt;/h3&gt;
    &lt;p&gt;Hi&lt;/p&gt;
    &lt;p&gt;Hello&lt;/p&gt;
    &lt;h3 id=&quot;second&quot;&gt;Second&lt;/h3&gt;
    &lt;p&gt;Bye&lt;/p&gt;
    &lt;p&gt;Goodbye&lt;/p&gt;

How can I programmatically check if an element, such as one of the `p`s, is after first `h3` and before the second `h3`, with jQuery?

I am trying to do something like this:

    $(p).each(function(){
       if($(this).isAfter(&quot;#first&quot;) &amp;&amp; $(this).isBefore(&quot;#second&quot;)) {
         // do stuff
       }
    });

Check if element is before or after another element in jQuery

Why is `08` considered an out of range int but `07` and below are not?

Why is 08 not a valid integer literal in Java?

<p>Why is <code>08</code> considered an out of range int but <code>07</code> and below are not?</p>


This is a basic question but I can&#39;t find an answer.  I&#39;ve looked into floating point arithmetic and a few other topics but nothing has seemed to address this.  I&#39;m sure I just have the wrong terminology.

Basically, I want to take two quantities - completed, and total - and divide them to come up with a percentage (of how much has been completed).  The quantities are `long`s.  Here&#39;s the setup:

    long completed = 25000;
    long total = 50000;

    System.out.println(completed/total);  // Prints 0

I&#39;ve tried reassigning the result to a double - it prints `0.0`.  Where am I going wrong?

Incidentally, the next step is to multiply this result by 100, which I assume should be easy once this small hurdle is stepped over.

BTW not homework here just plain old numskull-ness (and maybe too much coding today).

Division of integers in Java

I am working on a new `Android` project (`Java`), and created an Object with a large number of variables. Since I am planning to add getters and setters for all of them, I was wondering: is there a shortcut in `Eclipse` for automatically generating the getters and setters in a given class?

Is there a way to automatically generate getters and setters in Eclipse?

Imagine I have a query like 

    SELECT * from table1 a, table2 b where (WHATEVER)

Maybe both tables have the same column name. So I though it would be nice to access the data via

    resultSet.getString(&quot;a.columnName&quot;);
    resultSet.getString(&quot;b.columnName&quot;);

But this backfires on me and I get nothing. I read the API, but they don&#39;t really talk about this case. Is such a feature vendor dependent?


JDBC ResultSet get columns with table alias

I am trying to retrieve which day of the month it is.

Such as today is August 29,2011.

What i would like to do is just get the days number such as 29, or 30. Which ever day of the month it is. 

How would i go about doing this?

How to get day of the month?

Several times I&#39;ve been criticized for having suggested the use of the following methods:

 1. **setPreferredSize**
 2. **setMinimumSize**
 3. **setMaximumSize**

on `Swing` components. I don&#39;t see any alternative to their use when I want to define proportions between displayed components. I have been told this:

&gt; With layouts the answer is always the same: use a suitable
&gt; LayoutManager

I have searched the web a little bit, but I haven&#39;t found any comprehensive analysis of the subject. So I have the following questions:

 1. Should I completely avoid the use of those methods?
 2. The methods have been defined for a reason. So when should I use them? In which context? For what purposes? 
 3. What exactly are the negative consequences of using those methods? (I can only think adding portability between systems with different screen resolution).
 4. I don&#39;t think any LayoutManager can exactly satisfy all desired layout needs. Do I really need to implement a new LayoutManager for every little variation on my layout ? 
 5. If the answer to 4 is &quot;yes&quot;, won&#39;t this lead to a proliferation of LayoutManager classes which will become difficult to maintain?
 6. In a situation where I need to define proportions between children of a Component (eg, child1 should use 10% of space, child2 40% ,child3 50%), is it possible to achieve that without implementing a custom LayoutManager?

Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing?

I want to get only positive values, is there any way to prevent it using only html  
Please don&#39;t suggest validation method

![Screenshot of input control][1]


  [1]: http://i.stack.imgur.com/XiUmS.png

Is there any way to prevent input type=&quot;number&quot; getting negative values?

I just can&#39;t understand fixed point and floating point numbers due to hard to read definitions about them all over Google. But none that I have read provide a simple enough explanation of what they really are. Can I get a plain definition with example?

Fixed point vs Floating point number

I want to write fraction value such as the picture below:

![enter image description here][1]


  [1]: http://i.stack.imgur.com/sjKs8.jpg

How do I write fraction value using html without using image?

NOTE: I don&#39;t want this 1 1/2 pattern but strictly just as the pic above

How to write fraction value using html?

Wonder if there are any nontrivial ways of finding number&#39;s sign ([signum function](http://en.wikipedia.org/wiki/Signum_function))?  
May be shorter / faster / more elegant solutions than the obvious one

    var sign = number &gt; 0 ? 1 : number &lt; 0 ? -1 : 0;

------------

## Short answer!
Use this and you&#39;ll be safe and fast (source: [moz](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sign))
```js
if (!Math.sign) Math.sign = function(x) { return ((x &gt; 0) - (x &lt; 0)) || +x; };
```

You may want to look at performance and type-coercing comparison [fiddle](http://jsfiddle.net/disfated/NJFSa/)


&gt; Long time has passed. Further is mainly for historical reasons.



-----

## Results
For now we have these solutions:

-----------------------------------------------------------------------

**1.** Obvious and fast

    function sign(x) { return x &gt; 0 ? 1 : x &lt; 0 ? -1 : 0; }

-----------------------------------------------------------------------

**1.1.** Modification from [kbec](/users/854291/kbec) - one type cast less, more performant, shorter **[fastest]**

    function sign(x) { return x ? x &lt; 0 ? -1 : 1 : 0; }

_caution:_ `sign(&quot;0&quot;) -&gt; 1`

-----------------------------------------------------------------------

**2.** Elegant, short, not so fast **[slowest]**

    function sign(x) { return x &amp;&amp; x / Math.abs(x); }

_caution:_ `sign(+-Infinity) -&gt; NaN`, `sign(&quot;0&quot;) -&gt; NaN`

As of `Infinity` is a legal number in JS this solution doesn&#39;t seem fully correct.

-----------------------------------------------------------------------

**3.** The art... but very slow **[slowest]**

    function sign(x) { return (x &gt; 0) - (x &lt; 0); }

-----------------------------------------------------------------------

**4.** Using bit-shift  
    *fast, but `sign(-Infinity) -&gt; 0`*

    function sign(x) { return (x &gt;&gt; 31) + (x &gt; 0 ? 1 : 0); }

-----------------------------------------------------------------------

**5.** Type-safe **[megafast]**

**!** Seems like browsers (especially chrome&#39;s v8) make some magic optimizations and this solution turns out to be much more performant than others, even than (1.1) despite it contains 2 extra operations and logically never can&#39;t be faster.

    function sign(x) {
        return typeof x === &#39;number&#39; ? x ? x &lt; 0 ? -1 : 1 : x === x ? 0 : NaN : NaN;
    }

-----------------------------------------------------------------------

## Tools

 - [jsperf](http://jsperf.com/signs/3) preformance tests;
 - [fiddle](http://jsfiddle.net/disfated/NJFSa/) - type-cast tests;

Improvements are welcome!

-----------------------------------------------------------------------

### [Offtopic] Accepted answer

 - [Andrey Tarantsov](/a/14418335/489553) - +100 for the art, but sadly it is about 5 times slower than the obvious approach

 - [Fr&#233;d&#233;ric Hamidi](/a/7624945/489553) - somehow the most upvoted answer (for the time writing) and it&#39;s kinda cool, but it&#39;s definitely not how things should be done, imho. Also it doesn&#39;t correctly handle Infinity numbers, which are also numbers, you know.

 - [kbec](/a/9079549/489553) - is an improvement of the obvious solution. Not that revolutionary, but taking all together I consider this approach the best. Vote for him :)

Number.sign() in javascript

I have a variable that stores `false` or `true`, but I need `0` or `1` instead, respectively. How can I do this?

Convert boolean result into number/integer

In Python, I want to convert all strings in a list to integers.

So if I have:

    results = [&#39;1&#39;, &#39;2&#39;, &#39;3&#39;]

How do I make it:

    results = [1, 2, 3]


Convert all strings in a list to int

I need to convert a number into an unsigned byte. The number is always less than or equal to 255, and so it will fit in one byte.

I also need to convert that byte back into that number. How would I do that in Java? I&#39;ve tried several ways and none work. Here&#39;s what I&#39;m trying to do now:

    int size = 5;
    // Convert size int to binary
    String sizeStr = Integer.toString(size);
    byte binaryByte = Byte.valueOf(sizeStr);


and now to convert that byte back into the number:

    Byte test = new Byte(binaryByte);
    int msgSize = test.intValue();

Clearly, this does not work. For some reason, it always converts the number into `65`. Any suggestions?

How to Convert Int to Unsigned Byte and Back

I want to get two ints, one divided by the other to get a decimal or percentage.
How can I get a percentage or decimal of these two ints?
(I&#39;m not sure if it is right.. I&#39;m probably way off...)
for example:

    int correct = 25;
    int questionNum = 100;
    float percent = correct/questionNum *100;

This is how I thought I could do it, but it didn&#39;t work... I want to make the decimal (if there is one) into a percent out of 100 for example in this case it is %25. any ideas anyone?

Here is the correct code (thanks to Salvatore Previti!):
 
    float correct = 25;
    float questionNum = 100;
    float percent = (correct * 100.0f) / questionNum;
    

(btw, I am making a project using this for a quiz checking program that is why I need the percentage or decimal)

percentage of two int?

How can I convert an `Int` to a 7-character long `String`, so that `123` is turned into `&quot;0000123&quot;`?

How to convert an Int to a String of a given length with leading zeros to align?

How can I round a float up to the next integer value in objective C?

    1.1 -&gt; 2
    2.3 -&gt; 3
    3.4 -&gt; 4
    3.5 -&gt; 4
    3.6 -&gt; 4
    1.0000000001 -&gt; 2

Content Type	Original Author	Original Content on Stackoverflow
Question	user871303	View Question on Stackoverflow
Solution 1 - Java	Stuart Cook	View Answer on Stackoverflow
Solution 2 - Java	cwallenpoole	View Answer on Stackoverflow
Solution 3 - Java	Mahmoud Hanafy	View Answer on Stackoverflow
Solution 4 - Java	user149341	View Answer on Stackoverflow
Solution 5 - Java	Avijit Karmakar	View Answer on Stackoverflow
Solution 6 - Java	Ashwin J	View Answer on Stackoverflow

Why is 08 not a valid integer literal in Java?

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Check if element is before or after another element in jQuery

Android ImageButton with disabled UI feel

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