Category Archives: CS Courses

Calculator.cs

namespace ConsoleApp6.Math

{
    public class Calculator
    {
        public int Add(int a,int b)
        {
            return a + b;
        }
    }
}

namespace ConsoleApp6.Math

{

public class Calculator

{

public int Add(int a,int b)

{

return a + b;

}

Program.cs

using ConsoleApp6.Math;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp6
{
    class Program
    {
        static void Main(string[] args)
        {
            Person john = new Person();
            john.FirstName = "John";
            john.LastName = "Smith";
            john.Introduce();

            Calculator calculator = new Calculator();
            var result = calculator.Add(1, 2);
            System.Console.WriteLine(result);
        }
    }
}

using ConsoleApp6.Math;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace ConsoleApp6

{

class Program

{

static void Main(string[] args)

{

Person john = new Person();

john.FirstName = "John";

john.LastName = "Smith";

john.Introduce();

Calculator calculator = new Calculator();

var result = calculator.Add(1, 2);

System.Console.WriteLine(result);

}

Person.cs

using System;

namespace ConsoleApp6
{
    public class Person
    {
        public string FirstName;
        public string LastName;

        public void Introduce()
        {
            Console.WriteLine("My name is:"+FirstName+" "+LastName);
        }
    }
}

using System;

namespace ConsoleApp6

{

public class Person

{

public string FirstName;

public string LastName;

public void Introduce()

{

Console.WriteLine("My name is:"+FirstName+" "+LastName);

}

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Posted in C#, OOP

SOLID Concepts

Posted on June 23, 2017 | Leave a comment

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Posted in OO Analysis and Design, OOP

Object Oriented Programming Concepts

Posted on June 23, 2017 | Leave a comment

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Posted in OO Analysis and Design

OOP Clear

Posted on June 17, 2017 | Leave a comment

http://jompesh.com/videos/list/category/76

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Posted in OOP

Training Set, Validation Set, Test Set

Posted on May 28, 2017 | Leave a comment

Training Set is a subset of the dataset used to build predictive models.
Validation Set is a subset of the dataset used to assess the performance of model built in the training phase
– It provides a test platform for fine-tuning model’s parameters and selecting the best performing model
– Not all modeling algorithms need a validation set
Test set or unseen examples is a subset of the dataset to assess the likely future performance of a model.
– If a model fits the training set much better than it fits the test set. Overfitting is probably the cause

Binary Classification(two class classification)

true|false, 1|0, -1|+1, male|female

Multi-class classification problems can be seen as binary classification problems.

Model Evaluation:

https://en.wikipedia.org/wiki/Confusion_matrix

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Posted in Data Mining, Machine Learning

Tagged Model Evaluation

PHP OOP Project

Posted on April 22, 2017 | Leave a comment

Basic Simple Project By Me:

<?php

class Employee
{

    var $first;
    var $last;
    var $stat;
    var $uid;
    var $rate;
    var $hours;

    final public function __construct($f, $l, $st, $ui, $r, $ho)
    {
        $this->first = $f;
        $this->last = $l;
        $this->stat = $st;
        $this->uid = $ui;
        $this->rate = $r;
        $this->hours = $ho;
    }

    public function getALL()
    {
        echo "First Name:" . $this->first;
        echo "</br>";
        echo "Last Name:" . $this->last;
        echo "</br>";
        echo "Status:" . $this->stat;
        echo "</br>";
        echo "USerID:" . $this->uid;
        echo "</br>";
        echo "Pay Rate:$" . $this->rate;
        echo "</br>";
        echo "Housrs Worked:" . $this->hours;
        echo "</br>";
        echo "<b>Paycheck Amount:</b> $" . ($this->rate * $this->hours);
        echo "</br>";
        echo "</br>";

    }

}

class People extends Employee
{

}

$e = new People('JAddian', 'Forte', 'Manager', '521', '19', '40');
$e->getALL();

$e = new People('Victor', 'Davis', 'Assistant Manager', '231', '15', '33');
$e->getALL();

$e = new People('John', 'Clark', 'Worker', '687', '12', '26');
$e->getALL();

?>

<?php

class Employee

{

var $first;

var $last;

var $stat;

var $uid;

var $rate;

var $hours;

final public function __construct($f, $l, $st, $ui, $r, $ho)

{

$this->first = $f;

$this->last = $l;

$this->stat = $st;

$this->uid = $ui;

$this->rate = $r;

$this->hours = $ho;

}

public function getALL()

{

echo "First Name:" . $this->first;

echo "";

echo "Last Name:" . $this->last;

echo "";

echo "Status:" . $this->stat;

echo "";

echo "USerID:" . $this->uid;

echo "";

echo "Pay Rate:$" . $this->rate;

echo "";

echo "Housrs Worked:" . $this->hours;

echo "";

echo "Paycheck Amount: $" . ($this->rate * $this->hours);

echo "";

}

class People extends Employee

{

}

$e = new People('JAddian', 'Forte', 'Manager', '521', '19', '40');

$e->getALL();

$e = new People('Victor', 'Davis', 'Assistant Manager', '231', '15', '33');

$e->getALL();

$e = new People('John', 'Clark', 'Worker', '687', '12', '26');

$e->getALL();

By Others:
From OOP Fundamentals udemy Video project:

<?php

class Employee
{

    const MANAGER = 'MANAGER';
    const ASSISTANT_MANAGER='Assistant Manager';
    const WORKER='Worker';

//attributes
    protected $first;
    protected $last;
    protected $stat;
    protected $uid;
    protected $rate;
    protected $hours;

//class constructor
    final public function __construct($f, $l, $st, $ui, $r, $ho)
    {
        $this->first = $f;
        $this->last = $l;
        $this->stat = $st;
        $this->uid = $ui;
        $this->rate = $r;
        $this->hours = $ho;
    }

//function
    public function getALL()
    {
        echo "First Name:" . $this->first;
        echo "</br>";
        echo "Last Name:" . $this->last;
        echo "</br>";
        echo "Status:" . $this->stat;
        echo "</br>";
        echo "USerID:" . $this->uid;
        echo "</br>";
        echo "Pay Rate:$" . $this->rate;
        echo "</br>";
        echo "Housrs Worked:" . $this->hours;
        echo "</br>";
        echo "<b>Paycheck Amount:</b> $" . ($this->rate * $this->hours);
        echo "</br>";
        echo "</br>";
    }
} //end of employee class

class People extends Employee
{

}

$employee1 = new People('JAddian', 'Forte', People::MANAGER, '521', '19', '40');
$employee1->getALL();

$employee2 = new People('Victor', 'Davis', People::ASSISTANT_MANAGER, '231', '15', '33');
$employee2->getALL();

$employee3 = new People('John', 'Clark', Employee::WORKER, '687', '12', '26');
$employee3->getALL();

?>

<?php

class Employee

{

const MANAGER = 'MANAGER';

const ASSISTANT_MANAGER='Assistant Manager';

const WORKER='Worker';

//attributes

protected $first;

protected $last;

protected $stat;

protected $uid;

protected $rate;

protected $hours;

//class constructor

final public function __construct($f, $l, $st, $ui, $r, $ho)

{

$this->first = $f;

$this->last = $l;

$this->stat = $st;

$this->uid = $ui;

$this->rate = $r;

$this->hours = $ho;

}

//function

public function getALL()

{

echo "First Name:" . $this->first;

echo "";

echo "Last Name:" . $this->last;

echo "";

echo "Status:" . $this->stat;

echo "";

echo "USerID:" . $this->uid;

echo "";

echo "Pay Rate:$" . $this->rate;

echo "";

echo "Housrs Worked:" . $this->hours;

echo "";

echo "Paycheck Amount: $" . ($this->rate * $this->hours);

echo "";

}

} //end of employee class

class People extends Employee

{

}

$employee1 = new People('JAddian', 'Forte', People::MANAGER, '521', '19', '40');

$employee1->getALL();

$employee2 = new People('Victor', 'Davis', People::ASSISTANT_MANAGER, '231', '15', '33');

$employee2->getALL();

$employee3 = new People('John', 'Clark', Employee::WORKER, '687', '12', '26');

$employee3->getALL();

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Posted in OOP, PHP

PHP OOP: Class, Method, Object, Instance, Declare, Echo, Inheritance,Constructor,Access Control,Static!

Posted on April 18, 2017 | Leave a comment

PHP OOP example described here from edwin’s video:

<?php

class Car{
    var $wheels=4;
    var $hood=1;
    var $engine=1;
    var $doors=4;
    
    function MoveWheels(){
        //echo "Wheels move";
        //$this means reference inside the class for outside we need to create instance of a class with object and call by reference with variable or method to show;
        $this->wheels=4;
        
    }
    
    
    function CreateDoors(){
        $this->doors=6;
    }
}

$bmw=new Car(); //instance of the class
$truck=new Car(); //new instance for truck

$bmw->MoveWheels();
//$bmw->wheels=8;
echo $bmw->wheels."</br>";
echo $truck->wheels=10;
echo "<br>";
$truck->CreateDoors();
echo $truck->doors;

//if(class_exists("car", "MoveWheels")){
//    echo "Method Exists";
//}else{
//    echo "No";
//}
?>

<?php

class Car{

var $wheels=4;

var $hood=1;

var $engine=1;

var $doors=4;

function MoveWheels(){

//echo "Wheels move";

//$this means reference inside the class for outside we need to create instance of a class with object and call by reference with variable or method to show;

$this->wheels=4;

}

function CreateDoors(){

$this->doors=6;

}

$bmw=new Car(); //instance of the class

$truck=new Car(); //new instance for truck

$bmw->MoveWheels();

//$bmw->wheels=8;

echo $bmw->wheels."";

echo $truck->wheels=10;

echo " ";

$truck->CreateDoors();

echo $truck->doors;

//if(class_exists("car", "MoveWheels")){

// echo "Method Exists";

//}else{

// echo "No";

//}

Inheritance example:

<?php
class Car{

var $wheel=14;
var $hood=1;
var $engine=1;
var $doors=4;

function MoveWheeels(){
$this->wheels=14;
}

function CreateDoors(){
$this->doors=6;
}
}

class Plane extends Car{
 var $wheels=20;
}
$jet=new Plane();
echo $jet->wheels;
?>

<?php

class Car{

var $wheel=14;

var $hood=1;

var $engine=1;

var $doors=4;

function MoveWheeels(){

$this->wheels=14;

}

function CreateDoors(){

$this->doors=6;

}

class Plane extends Car{

var $wheels=20;

}

$jet=new Plane();

echo $jet->wheels;

Constructor:

<?php

class Car{
    var $wheels=4;
    var $hood=1;
    var $engine=1;
    var $doors=4;
    
    function __construct(){
        //echo "Wheels move";
        //$this means reference inside the class
       echo $this->wheels=4;
        
    }
    
    
    function CreateDoors(){
        echo $this->doors=6;
        echo "</br>";
    }
}


$truck=new Car();
echo "</br>";
echo $truck->CreateDoors();

?>

<?php

class Car{

var $wheels=4;

var $hood=1;

var $engine=1;

var $doors=4;

function __construct(){

//echo "Wheels move";

//$this means reference inside the class

echo $this->wheels=4;

}

function CreateDoors(){

echo $this->doors=6;

echo "";

}

$truck=new Car();

echo "";

echo $truck->CreateDoors();

Access control: Public, Private, Protected

<?php

class Car{
    public $wheels=4;
    protected $hood=1;
    private $engine=1;
    var $doors=4;
    
    function showProperty(){
        //echo "Wheels move";
        //$this means reference inside the class
        echo $this->engine;       
    }
}

$bmw=new Car(); //instance of the class
$semi=new Semi();
Class Semi extends Car{
    
    
}
echo $bmw->showProperty();
//echo $bmw->showProperty();
?>

<?php

class Car{

public $wheels=4;

protected $hood=1;

private $engine=1;

var $doors=4;

function showProperty(){

//echo "Wheels move";

//$this means reference inside the class

echo $this->engine;

}

$bmw=new Car(); //instance of the class

$semi=new Semi();

Class Semi extends Car{

}

echo $bmw->showProperty();

//echo $bmw->showProperty();

Static Data in Class:

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Posted in OOP, PHP

Tagged php OOP

Database Interview Questions

Posted on March 9, 2017 | Leave a comment

http://jompesh.com/videos/1/1760/lesson-26-database-normalization

Theory site: http://www.studytonight.com/dbms/generalization-and-specialization.php
Another Resource: http://www.guru99.com/database-normalization.html

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Posted in Database, SQL

SQL Join – Interview Clear

Posted on March 5, 2017 | Leave a comment

http://www.sql-join.com/sql-join-types/

In below: The relationship between the two tables is specified by the customer_id key, which is the “primary key” in customers table and a “foreign key” in the orders table:

customer_id	first_name	last_name	email	address	city	state	zipcode
1	George	Washington	[email protected]	3200 Mt Vernon Hwy	Mount Vernon	VA	22121
2	John	Adams	[email protected]	1250 Hancock St	Quincy	MA	02169
3	Thomas	Jefferson	[email protected]	931 Thomas Jefferson Pkwy	Charlottesville	VA	22902
4	James	Madison	[email protected]	11350 Constitution Hwy	Orange	VA	22960
5	James	Monroe	[email protected]	2050 James Monroe Parkway	Charlottesville	VA	22902

order_id
order_date
amount
customer_id

1
07/04/1776
$234.56
1

2
03/14/1760
$78.50
3

3
05/23/1784
$124.00
2

4
09/03/1790
$65.50
3

order_id	order_date	amount	customer_id
1	07/04/1776	$234.56	1
2	03/14/1760	$78.50	3
3	05/23/1784	$124.00	2
4	09/03/1790	$65.50	3

Note that (1) not every customer in our customers table has placed an order and (2) there are a few orders for which no customer record exists in our customers table.

Inner Join Query:

select first_name, last_name, order_date, amount
from customer
inner join orders
on customer.customer_id=orders.customer_id

select first_name, last_name, order_date, amount

from customer

inner join orders

on customer.customer_id=orders.customer_id

Result:

first_name	last_name	order_date	amount
george	washington	07/04/1776	$234.56
john	adams	05/23/1784	$124.00
Thomas	Jefferson	03/14/1760	$78.50
Thomas	Jefferson	09/03/1790	$65.50