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Showing posts from February, 2018

Encryption concept

Encryption is a process of hide original information. Only an authorized person can read the hidden information. Used for protecting information sent from one point to another especially over network. Plain-text is not encrypted information or the original text. Encryption key is a secret value applied to plain-text to encrypt information. Cipher-text is the result of encryption process or encrypted information. Same encryption key needed to reverse this process to get original text. The reverse process is called decryption. Example Let say we want to encrypt following message "hello world" . Assuming that we have a table that assign a decimal value for each characters, such as a = 1 , b=2 etc. and continues to capital letters. The table also has special characters like space which equal 0. (Please refer to ASCII table for actual representation of characters). By comparing our message and character integer table, the message is represented by following sequen
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Online gallery using div instead of table for page layout

Our online gallery up until previous post, used tables for setting layout for our gallery pages. Tables are primarily designed for tabulating data, not to layout page content. To define layout we should be using div tag. Our home page code shown below is modified to use div. To use div we should first get familiarized with CSS. <html>                <head>                               <title>Gallery| Home</title>                                                            <link rel="stylesheet" type = "text/css" href = "style/style.css">                                             </head>                <body>                                                                              <div style="width:20%; float:left;">                                              <!-- this is left space-->                               </div>                              
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Online gallery database

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In previous post, message sent by visitor does not get stored in database. To use database we need PHP to get the data, connect to database and save the data there in database. Database that we are going to use is MySQL. Easiest and quickest way too use PHP and MySQL is to install XAMPP. After install your XAMPP copy the gallery folder, into server htdoc folder. Now type localhost/gallery/home.html  URL in your browser. The browser should be able to open the gallery home page. Make sure you have started Apache and MySQL from XAMPP control panel. Before saving the message from visitor into database, we have to create a database first. To do that, go to  phpMyAdmin page and create a database called  gallery. After the database is created, create a table called messageTable . Below is the entity diagram that represent the table. Next, create a PHP file  in the gallery folder. Open notepad  and type the following code. Save the file as saveMessaageToDatabase.php and select
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Adding style to gallery

This post continues from previous blog where we  created online gallery website. In this post, we will add style to our pages. For this we will be using cascading styling sheet or CSS for short. The CSS codes are written inside notepad. Write the code written below in blank notepad (don't copy and paste) and save it as style.css in gallery folder.  a{                color: white;                background-color:gray;                padding: 15px;                text-decoration: none; } a:hover{                background-color:blue; } Don't forget to link this style sheet to your page. In home.html file, we need specify path to style sheet. Use <link> tag like shown below. <head> <title>Gallery| Home</title> <link rel="stylesheet" type = "text/css" href = "style.css"> </head> the hyperlinks now looks like button, when you move mouse on top of each bu
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building online gallery

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Purpose of this website is to showcase picture collections.  This website only contain static pages without any functionality. To concentrate on website building environment with readily available applications like notepad and browser. Before dive into coding, always do some sketches to design your website. A simple boxes with page name would be enough to give your overall idea. adding your website content and edit them is always easy to do with paper and pencil. Design comes handy when your project become big and complex.websites which contains static pages like home, about us and contact us. We add another page which is specific for this web site gallery. Once your design is ready, we can dive into coding. Create a folder in desktop and name it gallery , all files belongs to web site will be saved here. First thing we will do is write a template. Your home page will be template for other pages. All web pages consist of code HTML code: <html>       <head>
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Drawing Simple Pie Chart

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To draw pie chart with 5 sectors. The program calculates the total of all the input given by user and find the angle in degrees to draw each sectors. When the program first loads, chart based on default values is painted by the program. User can edit the values in the text field and presses draw button to redraw the chart. Each time the draw button is pressed, new set of angle is calculated and repainted. I have attached the the sources for this program. It is simple and needs upgrades. Pie.java This class executed the program and initializes the components JTextField and JPanel to draw the chart. package coolApp.graphics; import java.awt.*; import java.awt.event.*; import javax.swing.*; public class Pie { JTextField a,b,c,d,e; JButton btnDraw; double total; JPanel contentPane; Pie(){ JFrame frame = new JFrame("Pie - CoolApps"); frame.setSize(500,500); contentPane = new JPanel(); contentPane.setLayout(new BorderLayout()); frame
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VB.net connecting to SQL Server

Connecting to SQL server 2014 from VB.Net 2017, read values from the database and display the data in windows form. Before begin to write this program, first we need to import SqlClient class. Imports System.Data.SqlClient Step 1 Create a sql connection object. This is to make connection to object. Dim conn As New SqlConnection() Step 2 Set the connection string to the sqlconnection object: conn.ConnectionString = connStr Road block The variable connStr is a connection string. Connection object need connection string to make connection to database. It has information like who providing the database, the name of the database and some security information. Dim connStr As String = "Data Source = ServerInstanceName;Initial Catalog=testDB;Integrated Security=True" Let's break down the connection string into the three main components. Dim provider As String = "ServerInstanceName;" Dim database As String = "Initial Catalog=testDB;" Dim
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VB.net

a quick and convenient way to build a window based application. basically there is two main components in VB, the design view where we place the controls on a window form. then we have the code view where we write implementation for each controls on the form. Typically the control implementation or procedures are executed when certain events happens to the controls. Events like mouse click, or value change on text box, form load, form close and so on. After working with programming language like C, C++ and Java, getting use to VB is a bit challenging. its because first of all, VB don't use curly bracket to specify code blocks, and the statements don't end with semicolon. variable declaration for example is written as dim age As Integer in C, C++ and Java it written int age; in VB, variable declaration start with dim keyword, it means dimension and the functions are written as Function addNumber(ByVal num1 As Integer, ByVal num2 As Integer) As Integer addNumber
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