If you don&#39;t add `.0f` it will be treated like it is an integer, and an integer division is a lot different from a floating point division indeed :)

    float percent = (n * 100.0f) / v;

If you need an integer out of this you can of course cast the `float` or the `double` again in integer.

    int percent = (int)((n * 100.0f) / v);

If you know your n value is less than 21474836 (that is (2 ^ 31 / 100)), you can do all using integer operations.

    int percent = (n * 100) / v;

If you get NaN is because wathever you do you cannot divide for zero of course... it doesn&#39;t make sense.

Two options:

Do the division after the multiplication:

    int n = 25;
    int v = 100;
    int percent = n * 100 / v;

Convert an `int` to a `float` before dividing

    int n = 25;
    int v = 100;
    float percent = n * 100f / v;
    //Or:
    //  float percent = (float) n * 100 / v;
    //  float percent = n * 100 / (float) v;

One of them has to be a float going in. One possible way of ensuring that is:

    float percent = (float) n/v * 100;

Otherwise, you&#39;re doing [integer division, which truncates the numbers][1]. Also, you should be using `double` unless there&#39;s a good reason for the `float`.

The next issue you&#39;ll run into is that some of your percentages might look like 24.9999999999999% instead of 25%. This is due to precision loss in floating point representation. You&#39;ll have to decide how to deal with that, too. Options include a [DecimalFormat][2] to &quot;fix&quot; the formatting or [BigDecimal][3] to represent exact values.


  [1]: http://java.sun.com/docs/books/jls/third_edition/html/expressions.html#15.17.2
  [2]: http://download.oracle.com/javase/6/docs/api/java/text/DecimalFormat.html
  [3]: http://download.oracle.com/javase/6/docs/api/java/math/BigDecimal.html

    float percent = (n / (v * 1.0f)) *100

I have this table:

    Movies (ID, Genre)

A movie can have multiple genres, so an ID is not specific to a genre, it is a many to many relationship. I want a query to find the total number of movies which have at exactly 4 genres. The current query I have is 

      SELECT COUNT(*) 
        FROM Movies 
    GROUP BY ID 
      HAVING COUNT(Genre) = 4

However, this returns me a list of 4&#39;s instead of the total sum. How do I get the sum total sum instead of a list of `count(*)`?

mysql count group by having

I have an Apps Script that constantly gets this error. Judge by the notification email, it looks like the time limit is 5 minutes. Does anyone know if there is a way to extend this time limit? Or perhaps is there a way to call the Apps Script again and it pick up from where it left off? Any help is appreciated.


Exceeded maximum execution time in Google Apps Script

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?

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'm not sure if it is right.. I'm probably way off...)
for example:
<pre><code class="hljs language-ini">int correct = 25;
int questionNum = 100;
float percent = correct/questionNum *100;
</code></pre>
This is how I thought I could do it, but it didn'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!):
<pre><code class="hljs language-ini">float correct = 25;
float questionNum = 100;
float percent = (correct * 100.0f) / questionNum;
</code></pre>
(btw, I am making a project using this for a quiz checking program that is why I need the percentage or decimal)

From _Head First_ design patterns book, the singleton pattern with double checked locking has been implemented as below: 

    public class Singleton {
        private volatile static Singleton instance;
        private Singleton() {}
        public static Singleton getInstance() {
            if (instance == null) {
                synchronized (Singleton.class) {
                    if (instance == null) {
                        instance = new Singleton();
                    }
                }
            }
            return instance;
        }
    }

I don&#39;t understand why `volatile` is being used. Doesn&#39;t  `volatile` usage defeat the purpose of using double checked locking i.e performance?

Why is volatile used in double checked locking

A new feature coming in JDK 8 allows you to add to an existing interface while preserving binary compatibility.

The syntax is like

    public interface SomeInterface() {
      void existingInterface();
      void newInterface() default SomeClass.defaultImplementation;
    }

This way for all existing implementations of `SomeInterface` when they upgrade to this new version they don&#39;t all suddenly have compiles errors around `newInterface()`.

While this is neat, what happens when you are implementing two interfaces which both have added a new defaulted method which you did not implement?  Let me explain with an example.

    public interface Attendance {
       boolean present() default DefaultAttendance.present;
    }

    public interface Timeline {
       boolean present() default DefaultTimeline.present;
    }

    public class TimeTravelingStudent implements Attendance, Timeline {

    }

    // which code gets called?
    new TimeTravelingStudent().present();

Has this been defined as part of JDK 8 yet?

I found the Java gods talking about something similar here http://cs.oswego.edu/pipermail/lambda-lib/2011-February/000068.html, but its part of private mailing list and I cannot ask them directly.


See this for more details on how defaults are going to be used in JDK 8 and extending the Collection interface to support lambdas:
https://oracleus.wingateweb.com/published/oracleus2011/sessions/25066/25066_Cho223662.pdf

Are defaults in JDK 8 a form of multiple inheritance in Java?

I have the following hashmap in java:

&gt; {B046=0.0, A061=3.0, A071=0.0, B085=0.0, B075=3.0, B076=9.0, B086=3.0, B095=0.0, B096=0.0, A052=0.0, B066=0.0, B056=9.0, B065=0.0, B055=9.0}

How should I go about sorting the hashmap such that the Alphabet, followed by the numerical figures are taken into account?

The resulting hashmap should look like this:

&gt; {A052=0.0,A061=3.0,A071=0.0,B046=0.0,B055=9.0,B056=9.0,B065=0.0,B066=0.0,B075=3.0,B076=9.0,B085=0.0,B086=3.0,B095=0.0,B096=0.0}

Appreciate the help!

Sorting hashmap based on keys

I am displaying some text in a JLabel. Basically I am generating that text dynamically, and then I apply some HTML tags (e.g., `BR` and `B`) to format the text. Finally I assign this formatted text to my JLabel.

Now I want my Jlabel to automatically wrap the text to the next line when it reaches the end of screen, like the &quot;Word Wrap&quot; feature in Note Pad.

How can I do that?

Is there a &quot;word wrap&quot; property for JLabel?

Google Guava has CacheBuilder that allows to create ConcurrentHash with expiring keys that allow to remove entries after the fixed tiemout. However I need to cache only one instance of certain type.

What is the best way to cache single object within fixed timeout using Google Guava?

What is the best way to cache single object within fixed timeout?

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

Round a float up to the next integer in objective C?

&gt; **Possible Duplicate:**  
&gt; [mysql datatype for telephne number and address](https://stackoverflow.com/questions/1846254/mysql-datatype-for-telephne-number-and-address)  

&lt;!-- End of automatically inserted text --&gt;

Any suggestions on best practice to store telephone numbers in a DB? Consider a US phone number:

 - 555 555 1212
 - 555-555-1212
 - (555) 555 1212
 - 5555551212
 - 1-555-555-1212
 - 1 (555) 555-1212
 - and so on ...

Should I remove formatting and store only numbers? Should I just use one field -- or split them up into: country code, area code, phone number, etc.? Suggestions?

How to store phone numbers on MySQL databases?

In C# the following code returns 2:

    double d = 2.9;
    int i = (int)d;
    Debug.WriteLine(i);

In Javascript, however, the only way of converting a &quot;double&quot; to an &quot;int&quot; that I&#39;m aware of is by using Math.round/floor/toFixed etc. Is there a way of converting to an int in Javascript without rounding? I&#39;m aware of the performance implications of Number() so I&#39;d rather avoid converting it to a string if at all possible.

Converting a double to an int in Javascript without rounding

For example why can you do:

    int n = 9;

But not:

    Integer n = 9;


And you can do:

    Integer.parseInt(&quot;1&quot;);

But not:

    int.parseInt(&quot;1&quot;);

What is the difference between Integer and int in Java?

Sometimes, Activerecord data types confuse me. Err, often. One of my eternal questions is, for a given case,

&gt; Should I use `:decimal` or `:float`?


I&#39;ve often come across this link, *[ActiveRecord: :decimal vs :float?][1]*, but the answers aren&#39;t quite clear enough for me to be certain:

&gt; I&#39;ve seen many threads where people recommend flat out to never use
&gt; float and always use decimal. I&#39;ve also seen suggestions by some
&gt; people to use float for scientific applications only.

Here are some example cases:

 - Geolocation/latitude/longitude: `-45.756688`, `120.5777777`, ...
 - Ratio/percentage: `0.9`, `1.25`, `1.333`, `1.4143`, ...

I have used `:decimal` in the past, but I found dealing with `BigDecimal` objects in Ruby was unnecessarily awkward as compared to a float. I also know I can use `:integer` to represent money/cents, for example, but it doesn&#39;t quite fit for other cases, for example when quantities in which precision could change over time.

 - What are the advantages/disadvantages of using each?
 - What would be some good rules of thumb to know which type to use?

  [1]: http://railsforum.com/viewtopic.php?id=39211

Float vs Decimal in ActiveRecord

I have some Perl code where the hex() function converts hex data to decimal. How can I do it on [Python][1]?

  [1]: http://en.wikipedia.org/wiki/Python_%28programming_language%29


How do I convert hex to decimal in Python?

&gt; **Possible Duplicate:**  
&gt; [Round a double to 2 significant figures after decimal point](https://stackoverflow.com/questions/2808535/round-a-double-to-2-significant-figures-after-decimal-point)  

&lt;!-- End of automatically inserted text --&gt;

I know that there are plenty of examples on how to round this kind numbers.
But could someone show me how to round double, to get value that I can display as a 
String and ALWAYS have 2 decimal places?



Android - Round to 2 decimal places

I need to work with decimals.
In my program, the user need to put a number with decimals to convert that number.

The problem is: If I try to convert the argument into a number I get a integer without decimals.

    # ARGV[0] is: 44.33
    
    size = ARGV[0]
    
    puts size.to_i
    # size is: 44
    # :(

Convert string to decimal number in ruby

For a script I&#39;m writing, I need display a number that has been rounded, but not the decimal or anything past it. I&#39;ve gotten down to rounding it to the third place, but I&#39;m not sure how to go about just dropping the decimal and everything past it, as it doesn&#39;t seem like JavaScript has a `substr` function like PHP does.

Any recommendations?

Content Type	Original Author	Original Content on Stackoverflow
Question	Baruch	View Question on Stackoverflow
Solution 1 - Java	Salvatore Previti	View Answer on Stackoverflow
Solution 2 - Java	Eric	View Answer on Stackoverflow
Solution 3 - Java	Ryan Stewart	View Answer on Stackoverflow
Solution 4 - Java	Francisco Spaeth	View Answer on Stackoverflow

percentage of two int?

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

Solution 3 - Java

Solution 4 - Java

Exceeded maximum execution time in Google Apps Script

mysql count group by having

Attributions