How to set precision in C++

Praveen Kumar — Sun, 31 May 2009 23:10:13 +0000

In C++, you can use the ‘precision’ function to set the precision of the output. The function ‘precision’ is present in the header file ‘iostream.h’. The following,

cout.precision(n);

will have totally print ‘n’ d igits in the output with the decimal point in between(say ‘x’ before the decimal and ‘n-x’ after the decimal. The value of x will depend on the result). For example, if n = 4, the result is

0.2727 for 3/11, and
1.272 for 14/11

The example illustrated below provide a clear guidance on how to use the precision function. The Problem is to find the sum of ‘n’ numbers and then print the output in a single line.

#include<iostream>

using namespace std;

int main()
{
double a,s=0;
while( cin >> a )
{
s += a;
}
cout.precision(15);
cout<<s<<’\n’;
return 0;
}

How to create header files in C/C++ ?

Praveen Kumar — Wed, 25 Feb 2009 08:35:05 +0000

First of all, does creating a header file useful at all ? If yes how ?

It obviously is or else we wouldn’t have had soemthing called a ‘header files’.

Next, can we create our own header files ?

Yes, you can. It is pretty simple and its going to make your program simple and customizable.

Let us start with creating a header file in the traditional TurboC. Define the contents of the header file (meaning the functions you would like to include in the file) and then save it as a ‘.h’ file in the ‘include’ directory.

The path could be C:/TC/INCLUDE if you have installed Turbo C directly in ‘drive C’.

Your are done !! Include the header file in the program by just including the file like any other file.

#include “headerfilename.h” or #include<headerfilename.h>

Creating one in GCC is a bit more difficult. Define the file in the same way as stated above and save it in a ‘directory where you are going to save the program’ (NOTE: This is important. Both the header file and the program must be in the same directory, if not the program will not be able to detect your header file ). Header File successfully created ! But, unlike Turbo C the header file cannot be included by

#include<headerfilename.h>

The only way to include the header file is to treat the filename in the same way u treat a string.

#include “headerfilename.h”

Now that you have created your header files, you can create the function like sort, factorial etc. and store them in the header file. When you intend to use them, include the header file in the program and just call the function you stored in the header file.

Hasn’t id made life simple ?

PHP Class Header Files Handle

hlibco — Sun, 01 Jun 2008 19:05:53 +0000

Escrevi uma classe para manusear a inclusão dos arquivos CSS e Javascript no cabeçalho das páginas. Ele funciona da seguinte maneira:

Imagina que você tenha 10 arquivos CSS, e queira substituir estas 10 inclusões (http_requests) por apenas 2 inclusões. Ou seja, 2 arquivos CSS onde cada um deles tenha embutido, o conteúdo de 5 dos arquivos anteriores. Bom, legal, se fosse só pra isso, bastaria você utilizar uma classe de PHP Minify por exemplo a do VulgarisOverIp.

Mas a grande jogada aqui está no agrupamento dos arquivos, ou seja, você conseguir definir quaise arquivos estarão juntos em cada Package (para fazer o balanceamento de requests x peso por arquivo). E flexibilizar o REBUILD de cada package específico, caso 1 dos arquivos do pacote seja atualizado no futuro (não sendo necessário assim, re-criar todos os pacotes).

O resultado final desta classe PHP é:

<!– EMBEDED SCRIPTS CSS *************************************************** –>
<link rel=”stylesheet” type=”text/css” href=”http://www.exemplo.com/css/style.pk0.min_v.1.0.css” media=”screen”/>
<link rel=”stylesheet” type=”text/css” href=”http://www.exemplo.com/css/style.pk1.min_v.1.0.css” media=”screen”/>

<!– EMBEDED SCRIPTS JAVASCRIPT ******************************************** –>
<script type=”text/javascript” src=”http://www.exemplo.com/js/javascript.pk0.min_v.1.0.js”></script>
<script type=”text/javascript” src=”http://www.exemplo.com/js/javascript.pk1.min_v.1.0.js”></script>
<script type=”text/javascript” src=”http://www.exemplo.com/js/javascript.pk2.min_v.1.0.js”></script>

Olhando um pouco mais de perto, a estrutura funciona assim:

//Include the header files handle class file
include(PATH_CLASSES .’/class.headerfiles.php’);
$hFiles = new HeaderFiles;
$hFiles->path_root_CSS = ‘root/www/site/css’;
$hFiles->path_root_JS = ‘root/www/site/js’;
$hFiles->path_public_CSS = ‘http://www.example.com/css’;
$hFiles->path_public_JS = ‘http://www.example.com/js’;

// Setting the 2 packages of CSS files – do not use the enxtension file: .css (if the name is: style.css, just use style)
define(‘VERSION_CSS’, ‘1.0′);
define(‘SCRIPTS_CSS’, serialize(array(
‘0′=>array(‘file1′,
‘file2′,
‘1′=>array(‘file3′,
‘file4′,
‘file5′)
)));
define(‘REBUILD_CSS’, serialize(array(‘*’)));

// Generating Embeded CSS
$EMBEDED_SCRIPT_CSS = $hFiles->SetIncludeFiles(unserialize(SCRIPTS_CSS),’css’,VERSION_CSS,’site’,unserialize(REBUILD_CSS));

// Generating Embeded Javascript
// $EMBEDED_SCRIPT_JS = $hFiles->SetIncludeFiles(unserialize(SCRIPTS_JS),’js’,VERSION_JS,’site’,unserialize(REBUILD_JS));

echo $EMBEDED_SCRIPT_CSS;
// result: <link rel=”stylesheet” type=”text/css” href=”……

Para o caso do CSS, esta classe faz a função de MINIFY, retirando comentários e espaços em branco desnecessários dos arquivos CSS de origem. Porém, para os arquivos Javascript, ela apenas agrupa os arquivos dentro dos pacotes, sem fazer nenhuma alteração neles (reduzindo apenas o número de requisições HTTP).

O quê pode melhorar?

Incluir a chamada de alguma classe de MINIFY de Javascript, a fim de reduzir o tamanho (Kb) dos pacotes gerados.

Abaixo está o código completo da classe:

<?php

/**
* Project: headerFiles
* File: class.headerfiles.php
*
* Description:
*
* This class is used to manage CSS and JAVASCRIPT files in the header of the page.
* The main feature is not to compress or minify CSS and JS (but this class also do it).
*
* I was focused on really manage this files, what I mean is: Imagine that you
* have a set of 10 CSS files and 10 JS files, and you want to JOIN them into
* 2 packages of 5 files each. (CSS: pk0 , pk1 – JS: pk0, pk1)
*
* When you should to update one of these 5 files (of each pack), you can just
* rebuild the package number what it is inside (not the both package).
*
* With this class you can MINIFY some CSS files and JOIN JS files into some packages containing
* a certain number of files inside it.
*
* More practical:
define(‘VERSION_CSS’, ‘1.0′);
define(‘SCRIPTS_CSS’, serialize(array(
‘0′=>array(‘file1′,
‘file2′,
‘1′=>array(‘file3′,
‘file4′,
‘file5′)
)));
define(‘REBUILD_CSS’, serialize(array(‘*’)));
*
* This will generate 2 Packages (pk0 and pk1), with these CSS files inside it, without comments – minify version)
* The parameter ‘*’ is used to rebuild ALL Packages or generate it at the first time.
*
* If someday you update your ‘file2.css’, just rebuild the package 2 [ serialize(array('2')) ]
* or if you need to Rebuild more than one package, use: [ serialize(array('2','3','4')) ]
*
* @link http://hlibco.wordpress.com/
* @author Felipe Hlibco <hlibco at gmail dot com>
* @package Header
* @version 1.0.0
*/

/**
* USAGE EXAMPLE
* ————-

//Include the header files handle class file
include(PATH_CLASSES .’/class.headerfiles.php’);
$hFiles = new HeaderFiles;
$hFiles->path_root_CSS = ‘root/www/site/css’;
$hFiles->path_root_JS = ‘root/www/site/js’;
$hFiles->path_public_CSS = ‘http://www.example.com/css’;
$hFiles->path_public_JS = ‘http://www.example.com/js’;

// Setting the 2 packages of CSS files – do not use the enxtension file: .css (if the name is: style.css, just use style)
define(‘VERSION_CSS’, ‘1.0′);
define(‘SCRIPTS_CSS’, serialize(array(
‘0′=>array(‘file1′,
‘file2′,
‘1′=>array(‘file3′,
‘file4′,
‘file5′)
)));
define(‘REBUILD_CSS’, serialize(array(‘*’)));

// Generating Embeded CSS
$EMBEDED_SCRIPT_CSS = $hFiles->SetIncludeFiles(unserialize(SCRIPTS_CSS),’css’,VERSION_CSS,’site’,unserialize(REBUILD_CSS));

// Generating Embeded Javascript
// $EMBEDED_SCRIPT_JS = $hFiles->SetIncludeFiles(unserialize(SCRIPTS_JS),’js’,VERSION_JS,’site’,unserialize(REBUILD_JS));

echo $EMBEDED_SCRIPT_CSS;
*
*
*
*/

class HeaderFiles {

var $path_root_CSS;
var $path_root_JS;
var $path_public_CSS;
var $path_public_JS;

/* Public: Include CSS and Javascript files in the header */
/*
PARAMETERS:
$filenamePool: (string | array)
$fileType: (string) ‘css’ | ‘js’
$version: (string)
$pack : (integer) [0] Does not exists a default package [1] Exists a default package
$rebuild: (integer) [0] Do not rebuild ths script [1] Rebuild the script
*/
function SetIncludeFiles($packageFiles, $fileType, $version = ‘1.0′, $object = ’site’, $rebuild = 0)
{
/* Validate Version */
if (empty($version)) { $version = ‘1.0′; }

/* Add file type default settings */
if ($fileType == ‘css’)
{
$preName = ’style’;
$pathPublic = $this->path_public_CSS;
$pathRoot = $this->path_root_CSS;
}
elseif ($fileType == ‘js’)
{
$preName = ‘javascript’;
$pathPublic = $this->path_public_JS;
$pathRoot = $this->path_root_JS;
}

/* Identifying Object */
if ($object != ’site’)
{
$pathPublic .= ‘/’ . $object;
$pathRoot .= ‘/’ . $object;
}

/* Get the files parsed */
if (!is_array($filenamePool) && !empty($filenamePool))
{
$filenamePool = array($filenamePool);
}

/* For each file parsed into package, loop */
foreach($packageFiles as $package=>$files)
{
/* Generate the filename for each object type */
if ($object == ’site’)
{
$filename = $preName . ‘.pk’ . $package . ‘.min_v.’ . $version . ‘.’ . $fileType;
}
else
{
/* Just allow 1 script file per object (film / filmclub / theater) */
$filename = $packageFiles[0] . ‘.’ . $fileType;
}

/* Validate rebuild activation */
if (!is_array($rebuild)) { $rebuild = array(); }

/* Rebuild some specified package or Re-generate all packages ‘*’ */
if (in_array($package,$rebuild) || in_array(‘*’,$rebuild))
{
/* Handle Files from diferent way */
if ($fileType == ‘css’)
{
foreach($files as $file)
{
$content = file_get_contents($pathRoot . ‘/’ . $file . ‘.’ . $fileType);
$packageContent .= str_replace(‘; ‘,’;',str_replace(‘ }’,'}’,str_replace(‘{ ‘,’{‘,str_replace(array(“\r\n”,”\r”,”\n”,”\t”,’ ‘,’ ‘,’ ‘),”",preg_replace(‘!/\*[^*]*\*+([^/][^*]*\*+)*/!’,”,$content)))));
}
}
elseif ($fileType == ‘js’)
{
foreach($files as $file)
{
$packageContent .= file_get_contents($pathRoot . ‘/’ . $file . ‘.’ . $fileType);
}
}

$fp = fopen($pathRoot . ‘/’.$filename, ‘w+’);
fwrite($fp, $packageContent);
fclose($fp);
unset($packageContent);
}

/* Generating Tag */
if ($fileType == ‘css’)
{
$outputTag .= ‘<link rel=”stylesheet” type=”text/css” href=”‘ . $pathPublic . ‘/’ . $filename . ‘” media=”screen”/>’ . “\r\n”;
}
elseif ($fileType == ‘js’)
{
$outputTag .= ‘<script type=”text/javascript” src=”‘ . $pathPublic . ‘/’ . $filename . ‘”></script>’ . “\r\n”;
}
}

/* Return the content */
return $outputTag;
}

}
?>

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How to set precision in C++

How to create header files in C/C++ ?

PHP Class Header Files Handle