calculator database using php

Hi all this post explains implementation of calculator database in php
you are required to write the following set of instructions here.


<TITLE>PHP Calculator v1</TITLE>
<form name="calc" action="?page=calc" method="POST"> <!--implementing pagination with the page name appended to url -->
Number 1: <input type=text name=value1><br>
Number 2: <input type=text name=value2><br>
Operation: <input type="submit" name=oper value="add"/> <input type="submit" name=oper value="subtract"/>
<input type="submit" name=oper value="divide"/> <input type="submit" name=oper value="multiply"/><br>
</form>

<?php
if($_SERVER['REQUEST_METHOD'] === 'POST')//checking if the form method is post
{
$page = $_GET['page'];  
// Defining the "calc" class
class calc {
var $number1;  //variable declaration
var $number2;  
function add($number1,$number2)  {
$con=db();       //creating connection variable            
$result =$number1 + $number2;
echo("The sum of $number1 and $number2 is $result<br><br>");
echo("$number1 + $number2 = $result");
mysqli_query($con,"insert into plus values('$number1 + $number2',$result)");
exit;            
}  
function subtract($number1,$number2)  {
$con=db();                  
$result =$number1 - $number2;
echo("The difference of $number1 and $number2 is $result<br><br>");
echo("$number1 &#045 $number2 = $result");
mysqli_query($con,"insert into plus values('$number1 - $number2',$result)");
exit;          
 }  
function divide($number1,$number2)  {
$con=db();                  
$result =$number1 / $number2;
echo("$number1 divided by $number2 is $result<br><br>");
echo("$number1 &divide $number2 = $result");
mysqli_query($con,"insert into plus values('$number1 / $number2',$result)");
exit;          
 }  
function multiply($number1,$number2)  {
$con=db();                  
$result =$number1 * $number2;
echo("The product of $number1 and $number2 is $result<br><br>");
echo("$number1 x $number2 = $result");
mysqli_query($con,"insert into plus values('$number1 * $number2',$result)");
exit;            
}
}
$calc = new calc();
 ?>

<?php
if($page == "calc"){
$n1 = $_POST['value1'];
$n2 = $_POST['value2'];
$number1=abs(ltrim($n1,''));
$number2=abs(ltrim($n2,''));
$oper = $_POST['oper'];
function db () {
static $con;
if ($con===NULL){        
$con = mysqli_connect ("localhost", "root", "", "plus");
     }
return $con;
 }
if(!$number1){
echo("You must enter number 1!");
exit;    
 }
if(!$number2){
echo("You must enter number 2!");
exit;      
}
if(!$oper){
echo("You must select an operation to do with the numbers!");
exit;      
}
if(!preg_match("/[0-9]/", $number1)){
echo("Number 1 MUST be numbers!");
exit;      
}
if(!preg_match("/[0-9]/", $number2)){
echo("Number 2 MUST be numbers!");
exit;      
}
if($oper == "add"){          
$con=db();
$query = mysqli_query($con,"SELECT * FROM plus WHERE exp='$number1 + $number2'");
if (!$query) {
        echo 'MySQL Error: ' . mysqli_error();
        exit;
    }
$numrows = mysqli_num_rows($query);
if ($numrows == 0) {
$calc->add($number1,$number2);
      }

}
if($oper == "subtract"){
$con=db();
$query = mysqli_query($con,"SELECT * FROM plus WHERE exp='$number1 - $number2'");
$numrows = mysqli_num_rows($query);
if ($numrows == 0) {        
$calc->subtract($number1,$number2);
      } }
if($oper == "divide"){
$con=db();
$query = mysqli_query($con,"SELECT * FROM plus WHERE exp='$number1 / $number2'");
$numrows = mysqli_num_rows($query);
if ($numrows == 0) {  
          $calc->divide($number1,$number2);    
 }
}
 if($oper == "multiply"){
$con=db();
$query = mysqli_query($con,"SELECT * FROM plus WHERE exp='$number1 * $number2'");
$numrows = mysqli_num_rows($query);
if ($numrows == 0) {  
          $calc->multiply($number1,$number2);       } }
while ($row = mysqli_fetch_assoc($query)) {
print("Accessed from database.......<br>");
print($row['exp'] . " = " . $row['res']);
 }    
}
}
?>

Java Script programs on displaying country's capital

Write an HTML page that contains a selection box with a list of 5 countries. When the user selects a country, its capital should be printed next to the list. Add CSS to customize the properties of the font of the capital (color, bold and font size).  


As we all know Javascript can change HTML content.One of javascript HTML method is getElementById()

This example uses the method to "find" an HTML element (with id="txtSelectedCapital") and changes the element content (innerHTML) to "selectedValue":

dropDown.options[dropDown.selectedIndex].value;

This line allows us to select the drop down list value based on the index and store it in some variable for displaying in the browser.

WTLAB program to implement PASSWORD MISMATCH using servlets

A web application for implementation: The user is first served a login page which takes user’s name and password. After submitting the details the server checks these values against the data from a database and takes following decisions. If name and password matches, serves a welcome page with user’s full name. If name matches and password doesn’t match, then serves “password mismatch “page. 
If name is not found in database serves a registration page where user’s full name is asked and on submitting the details are stored in database

To implement the above program using servlets all u require is :
1.Tomcat container
2.Notepad
3.Browser
4.Connector.jar file which is to be placed in tomcat's lib folder

Initially u have to create a folder structure as follows:

As u can see in the above image the html files are kept outside.It is your choice to keep it in src folder or not.

The login.html file consist of 

 Focus on the action attribute in the above form, the url port number may change based on ur tomcats setting.

The regi.html file consist of 

The WEB-INF directory consists of 

 The classes folder may consist of  all the java files and .class files as follows

The servlet process.java has following set of instructions:

The servlet regi.java has following

Open mysql and create the required database and tables as follows

After writing the java files u have to compile it in cmd prompt

Once compiled move out of classes folder and type web.xml contents

Open Tomcat and type the url of ur project

Initially i assumed no user information is present in the database so u will be redirected to registration page.

After registration u will be asked to login ,These are the details of the registered user in mysql.

Once u specify the password and username u will get successfull response.

If by mistake u forgot and specified wrong password u will get the following message.

This is it.Same logic we can implement in jsp and php as well.U can also use framesets for this program just like i discussed in my previous posts.Do not stick to same program try to use either bootstrap or manual css for enhancing its looks.

Hope this post is useful to all who are watching right now.