Once you read what [*What Every Computer Scientist Should Know About Floating-Point Arithmetic*][1] you could use the [`.toFixed()`][2] function:

    var result = parseFloat(&#39;2.3&#39;) + parseFloat(&#39;2.4&#39;);
    alert(result.toFixed(2));​


  [1]: http://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html
  [2]: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Number/toFixed

    (parseFloat(&#39;2.3&#39;) + parseFloat(&#39;2.4&#39;)).toFixed(1);

its going to give you solution i suppose 

I&#39;ve stored user settings in the SharedPreferences in my App. What will happen with the SharedPreferences when I update the App via Google Play Store to a new version of the App? 

Will the SharedPrefernces still be there after the update or will they be deleted?

So far I haven&#39;t found an answer on the web or Stackoverflow.

Can you point me to some links they describe this process?


**Edit:**
Meanwhile I found an other answer as well: https://stackoverflow.com/questions/7103453/sharedpreferences-update-unisntall

**Edit 2:**
Since time past quite a bit when I first asked this question I recently learned that since Android 6.0 (API 23) it is also possible to use the auto backup functionality to *secure* your shared preferences as described by [Google here][1].

Just add the `allowBackup=&quot;true&quot;` in your `AndroidManifest.xml` file.


  [1]: https://developer.android.com/guide/topics/data/autobackup.html

What will happen to the SharedPreferences on update an Android App?

I am attempting to run an application in IIS8 that has the following in the config:

    &lt;modules runAllManagedModulesForAllRequests=&quot;true&quot; /&gt;

IIS8 is giving me an error that says...

&gt; This configuration section cannot be used at this path. This happens
&gt; when the section is locked at a parent level. Locking is either by
&gt; default (overrideModeDefault=&quot;Deny&quot;), or set explicitly by a location
&gt; tag with overrideMode=&quot;Deny&quot; or the legacy allowOverride=&quot;false&quot;.

I&#39;m guessing by the error and a quick SO search that there is some higher level security setting that&#39;s preventing that line from being allowed. Any ideas?

IIS8 Win8 and runAllManagedModulesForAllRequests=&quot;true&quot;

&gt; **Possible Duplicate:**  
&gt; [Is JavaScript&amp;#39;s Math broken?](https://stackoverflow.com/questions/588004/is-javascripts-math-broken)  

&lt;!-- End of automatically inserted text --&gt;

I&#39;m calculating the sum of several float values using javascript and... I&#39;ve noticed a strange thing never seen before. Executing this code:

    parseFloat(&#39;2.3&#39;) + parseFloat(&#39;2.4&#39;)

I obtain **4.699999999999999**

So... what sould I do to obtain a correct value? (supposed that this is incorrect...)



Float sum with javascript

> Possible Duplicate: 
> <a href="https://stackoverflow.com/questions/588004/is-javascripts-math-broken" target="_blank" rel="noopener noreferrer">Is JavaScript's Math broken?</a>

I'm calculating the sum of several float values using javascript and... I've noticed a strange thing never seen before. Executing this code:
<pre><code class="hljs language-javascript">parseFloat('2.3') + parseFloat('2.4')
</code></pre>
I obtain 4.699999999999999
So... what sould I do to obtain a correct value? (supposed that this is incorrect...)

    var timeInMs = Date.now();

per [MDN][1]

vs.

    var timeInMs = new Date(optional).getTime();

per [MDN][2].

Is there any difference between the two, besides the syntax and the ability to set the Date (to not the current) via optional in the second version?

Date.now() is faster - check out the [jsperf][3]


  [1]: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Date/now
  [2]: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Date/getTime
  [3]: http://jsperf.com/gettime-vs-now-0

Performance - Date.now() vs Date.getTime()

I just came across a blog that mentions a `j` function in Rails.  They were using it to do ajax style page updates.

    $(&#39;#cart&#39;).html(&quot;&lt;%=j render @cart %&gt;&quot;);

I get they are using partials to render the `cart` partial, but whats the point of `j`? I&#39;ve found some articles that say it converts the string to something JavaScript will accept, but what does that mean?

What does the j function in Rails do?

**UPDATE:** [Colin][1]&#39;s suggestion of removing the line //= require_tree . has fixed the issue.

I have wasted over 2 days trying to follow every suggestion out there and fix my issue. I am trying to follow the http://ruby.railstutorial.org book on windows machine and cannot for the life of me get past the following nasty error.

    ExecJS::RuntimeError in Static_pages#home

    Showing C:/Users/.../bootcamp-sample-app/app/views/layouts/application.html.erb where line #6 raised:

    [&quot;ok&quot;,&quot;(function() {\n\n\n\n}).call(this);\n&quot;]
    (in C:/Users/.../bootcamp-sample-app/app/assets/javascripts/sessions.js.coffee)
    Extracted source (around line #6):

    3: &lt;head&gt;
    4:   &lt;title&gt;&lt;%= full_title(yield(:title)) %&gt;&lt;/title&gt;
    5:   &lt;%= stylesheet_link_tag    &quot;application&quot;, media: &quot;all&quot; %&gt;
    6:   &lt;%= javascript_include_tag &quot;application&quot; %&gt;
    7:   &lt;%= csrf_meta_tags %&gt;
    8:   &lt;%= render &#39;layouts/shim&#39; %&gt;
    9: &lt;/head&gt;
    Rails.root: C:/Users/.../bootcamp-sample-app

    Application Trace | Framework Trace | Full Trace
    app/views/layouts/application.html.erb:6:in `_app_views_layouts_application_html_erb___487732698_30422172&#39;
    Request


I have tried every suggestion including installing nodejs with the msi, using execjs 1.3.0 and other things which I can&#39;t even remember any more. Here is the **gem file** 

    source &#39;https://rubygems.org&#39;
    
    gem &#39;rails&#39;, &#39;3.2.8&#39;
    gem &#39;bootstrap-sass&#39;, &#39;2.0.0&#39;
    gem &#39;bcrypt-ruby&#39;, &#39;3.0.1&#39;
    gem &#39;faker&#39;, &#39;1.0.1&#39;
    gem &#39;will_paginate&#39;, &#39;3.0.3&#39;
    gem &#39;bootstrap-will_paginate&#39;, &#39;0.0.6&#39;
    
    group :development, :test do
      gem &#39;sqlite3&#39;, &#39;1.3.5&#39;
      gem &#39;rspec-rails&#39;, &#39;2.10.0&#39;
      gem &#39;guard-rspec&#39;, &#39;0.5.5&#39;
      gem &#39;guard-cucumber&#39;
    end
    
    group :development do
      gem &#39;annotate&#39;, &#39;2.5.0&#39;
    end
    
    
    # Gems used only for assets and not required
    # in production environments by default.
    group :assets do
      gem &#39;sass-rails&#39;
      gem &#39;coffee-rails&#39;
      gem &#39;coffee-script&#39;
      gem &#39;uglifier&#39;
    end
    
    gem &#39;jquery-rails&#39;, &#39;2.0.2&#39;
    
    gem &#39;execjs&#39;
    
    # Gems on Linus/Mac
    #gem &#39;therubyracer&#39;
    
    
    group :test do
      gem &#39;capybara&#39;, &#39;1.1.2&#39;
      gem &#39;guard-spork&#39;, &#39;0.3.2&#39;
      gem &#39;spork&#39;, &#39;0.9.0&#39;
      gem &#39;factory_girl_rails&#39;, &#39;1.4.0&#39;
      gem &#39;cucumber-rails&#39;, &#39;1.2.1&#39;, require: false
      gem &#39;database_cleaner&#39;, &#39;0.7.0&#39;
    
    
    # Test gems on Linux
    #  gem &#39;rb-inotify&#39;, &#39;0.8.8&#39;
    #  gem &#39;libnotify&#39;, &#39;0.5.9&#39;
    
    # Test gems on Macintosh OS X
    #  gem &#39;selenium-webdriver&#39;, &#39;~&gt; 2.22.0&#39;
    #  gem &#39;rb-fsevent&#39;, &#39;0.9.1&#39;, :require =&gt; false
    #  gem &#39;growl&#39;, &#39;1.0.3&#39;
    
    # Test gems on Windows
    # gem &#39;rb-fchange&#39;, &#39;0.0.5&#39;
    # gem &#39;rb-notifu&#39;, &#39;0.0.4&#39;
    # gem &#39;win32console&#39;, &#39;1.3.0&#39;
    end
    
    group :production do
    #  gem &#39;therubyracer&#39;
      gem &#39;pg&#39;, &#39;0.12.2&#39;
    end
    
    # To use ActiveModel has_secure_password
    # gem &#39;bcrypt-ruby&#39;, &#39;~&gt; 3.0.0&#39;
    
    # To use Jbuilder templates for JSON
    # gem &#39;jbuilder&#39;
    
    # Use unicorn as the app server
    # gem &#39;unicorn&#39;
    
    # Deploy with Capistrano
    # gem &#39;capistrano&#39;
    
    # To use debugger
    #gem &#39;debugger&#39;&#39;

and here is the **sessions.js.coffee**

    # Place all the behaviors and hooks related to the matching controller here.
    # All this logic will automatically be available in application.js.
    # You can use CoffeeScript in this file: http://jashkenas.github.com/coffee-script/

**application.js**

    // This is a manifest file that&#39;ll be compiled into application.js, which will include all the files
    // listed below.
    //
    // Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
    // or vendor/assets/javascripts of plugins, if any, can be referenced here using a relative path.
    //
    // It&#39;s not advisable to add code directly here, but if you do, it&#39;ll appear at the bottom of the
    // the compiled file.
    //
    // WARNING: THE FIRST BLANK LINE MARKS THE END OF WHAT&#39;S TO BE PROCESSED, ANY BLANK LINE SHOULD
    // GO AFTER THE REQUIRES BELOW.
    //
    //= require jquery
    //= require jquery_ujs
    //= require_tree .
    //= require bootstrap

**application.html.erb**

    &lt;!DOCTYPE html&gt;
     &lt;html&gt;
     &lt;head&gt;
       &lt;title&gt;&lt;%= full_title(yield(:title)) %&gt;&lt;/title&gt;
       &lt;%= stylesheet_link_tag    &quot;application&quot;, media: &quot;all&quot; %&gt;
       &lt;%= javascript_include_tag &quot;application&quot; %&gt;
       &lt;%= csrf_meta_tags %&gt;
       &lt;%= render &#39;layouts/shim&#39; %&gt;
     &lt;/head&gt;
     &lt;body&gt;
     &lt;%= render &#39;layouts/header&#39; %&gt;
     &lt;div class=&quot;container&quot;&gt;
       &lt;%= yield %&gt;
       &lt;%= render &#39;layouts/footer&#39; %&gt;
     &lt;/div&gt;
     &lt;/body&gt;
     &lt;/html&gt;

Here is **console content**

    Processing by StaticPagesController#home as HTML
      Rendered static_pages/home.html.erb within layouts/application (45.0ms)
    Completed 500 Internal Server Error in 1136ms

    ActionView::Template::Error ([&quot;ok&quot;,&quot;(function() {\n\n\n\n}).call(this);\n&quot;]
      (in C:/Users/.../bootcamp-sample-app/app/assets/javascripts/sessions.js.coffee)):
        3: &lt;head&gt;
        4:   &lt;title&gt;&lt;%= full_title(yield(:title)) %&gt;&lt;/title&gt;
        5:   &lt;%= stylesheet_link_tag    &quot;application&quot;, media: &quot;all&quot; %&gt;
        6:   &lt;%= javascript_include_tag &quot;application&quot; %&gt;
        7:   &lt;%= csrf_meta_tags %&gt;
        8:   &lt;%= render &#39;layouts/shim&#39; %&gt;
        9: &lt;/head&gt;
      app/views/layouts/application.html.erb:6:in `_app_views_layouts_application_html_erb___487732698_30422172&#39;


      Rendered C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/_trace.erb (2.0ms)
      Rendered C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (1.0ms)
      Rendered C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/template_error.erb within rescues/layout (34.0ms)


I have installed Devkit and have tried various gems but please suggest changes which can help me develop on windows. I used rubyinstaller for everything.

What am I missing?


  [1]: https://stackoverflow.com/users/1017768/colin-r

ExecJS::RuntimeError on Windows trying to follow rubytutorial

Is there a js listener for when a user scrolls in a certain textbox that can be used? Kinda like onclick except for scrolling. I saw https://stackoverflow.com/questions/5669207/html5-event-listener-for-number-input-scroll-chrome-only but that seems to be for chrome only. I&#39;m looking for something cross-browser.

Scroll event listener javascript

I&#39;m using express + node.js and I have a req object, the request in the browser is /account but when I log req.path I get &#39;/&#39; --- not &#39;/account&#39;.

      //auth required or redirect
      app.use(&#39;/account&#39;, function(req, res, next) {
        console.log(req.path);
        if ( !req.session.user ) {
          res.redirect(&#39;/login?ref=&#39;+req.path);
        } else {
          next();
        }
      });


req.path is / when it should be /account ??

how to get request path with express req object

There are n people numbered from `1` to `n`. I have to write a code which produces and print all different combinations of `k` people from these `n`. Please explain the algorithm used for that. 

Creating all possible k combinations of n items in C++

I am trying to calculate the distance between two positions on a map.
I have stored in my data: Longitude, Latitude, X POS, Y POS.

I have been previously using the below snippet.

    DECLARE @orig_lat DECIMAL
    DECLARE @orig_lng DECIMAL
    SET @orig_lat=53.381538 set @orig_lng=-1.463526
    SELECT *,
    	3956 * 2 * ASIN(
              SQRT( POWER(SIN((@orig_lat - abs(dest.Latitude)) * pi()/180 / 2), 2) 
                  + COS(@orig_lng * pi()/180 ) * COS(abs(dest.Latitude) * pi()/180)  
                  * POWER(SIN((@orig_lng - dest.Longitude) * pi()/180 / 2), 2) )) 
              AS distance
    --INTO #includeDistances
    FROM #orig dest


I don&#39;t however trust the data coming out of this, it seems to be giving slightly inaccurate results.

Some sample data in case you need it 

    Latitude	    Longitude     Distance 
    53.429108	    -2.500953     85.2981833133896

Could anybody help me out with my code, I don&#39;t mind if you want to fix what I already have if you have a new way of achieving this that would be great.

Please state what unit of measurement your results are in.

Calculating distance between two points (Latitude, Longitude)

I don&#39;t know it my nomenclature is correct! Anyway, these are the integer I have, for example :

    76
    121
    9660

And I&#39;d like to round them to the close hundred, such as they must become :

    100
    100
    9700

How can I do it faster in C#? I think about an algorithm, but maybe there are some utilities on C#?

How to round a integer to the close hundred?

I have two rectangles characterized by 4 values each : 

Left position `X`, top position `Y`, width `W` and height `H`:

    X1, Y1, H1, W1
    X2, Y2, H2, W2

Rectangles are not rotated, like so:

    +--------------------&gt; X axis
    |
    |    (X,Y)      (X+W, Y)
    |    +--------------+
    |    |              |
    |    |              |
    |    |              |
    |    +--------------+
    v    (X, Y+H)     (X+W,Y+H)
    
    Y axis

What is the best solution to determine whether the intersection of the two rectangles is empty or not?

Two Rectangles intersection

Is there a way to round a python float to x decimals? For example:

    &gt;&gt;&gt; x = roundfloat(66.66666666666, 4)
    66.6667
    &gt;&gt;&gt; x = roundfloat(1.29578293, 6)
    1.295783

I&#39;ve found ways to trim/truncate them (66.666666666 --&gt; 66.6666), but not round (66.666666666 --&gt; 66.6667).

Round float to x decimals?

    float a = 0;
    while (true)
    {
        a++;
        if (a &gt; 16777216)
            break; // Will never break... a stops at 16777216
    }

Can anyone explain this to me why a float value stops incrementing at 16777216 in this code?

**Edit:**

Or even more simple:

    float a = 16777217; // a becomes 16777216


Why does a float variable stop incrementing at 16777216 in C#?

I am trying to divide two image widths in a Bash script, but bash gives me `0` as the result:

    RESULT=$(($IMG_WIDTH/$IMG2_WIDTH))

I did study the Bash guide and I know I should use `bc`, in all examples in internet they use `bc`. In `echo` I tried to put the same thing in my `SCALE` but it didn&#39;t work.

Here is the example I found in the tutorials:

    echo &quot;scale=2; ${userinput}&quot; | bc 

How can I get Bash to give me a float like `0.5`?

How do I use floating-point arithmetic in bash?

How can I find the index of the minimum item in a Python list of floats? If they were integers, I would simply do:

    minIndex = myList.index(min(myList))

However, with a list of floats I get the following error, I assume because float equality comparison is rather iffy.

    ValueError: 0.13417985135 is not in list

Now, I know that I could simply scroll through the list and compare each item to see whether it is &lt; (min + 0.0000000000001) and &gt; (min - 0.0000000000001), but that is kinda messy. Is there a more elegant (preferably built-in) way to find the index of the smallest item in a list of floats?

Python: Find index of minimum item in list of floats

I have the following code:

    Double i=17.31;
    long j=(long) (i*100);
    System.out.println(j);
    
O/P : `1730   //Expected:1731`

    
    Double i=17.33;
    long j=(long) (i*100);
    System.out.println(j);
    
O/P : `1732    //Expected:1733`

    Double i=17.32;
    long j=(long) (i*100);
    System.out.println(j);
    
O/P : `1732    //Expected:1732{As expected}`

    Double i=15.33;
    long j=(long) (i*100);
    System.out.println(j);
    
O/P : `1533    //Expected:1533{as Expected}`


I have tried to Google but unable to find reason.I am sorry if the question is trivial. 



Double multiplied by 100 and then cast to long is giving wrong value

Does a float have 32 binary digits and a double have 64 binary digits? The documentation was too hard to make sense of.

Do all of the bits translate to significant digits? Or does the location of the decimal point take up some of the bits?

Content Type	Original Author	Original Content on Stackoverflow
Question	davioooh	View Question on Stackoverflow
Solution 1 - Javascript	Darin Dimitrov	View Answer on Stackoverflow
Solution 2 - Javascript	Gyan Chandra Srivastava	View Answer on Stackoverflow

Float sum with javascript

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Solution 2 - Javascript

IIS8 Win8 and runAllManagedModulesForAllRequests="true"

What will happen to the SharedPreferences on update an Android App?

Attributions