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using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Mail;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace smtp1
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            try
            {
                // Create the email
                MailMessage mail = new MailMessage();
                mail.To.Add(TextBox1.Text);  // Recipient email (from input)
                mail.From = new MailAddress("helloeventplanner2025@gmail.com");
                mail.Subject = TextBox2.Text; // Subject from input
                mail.Body = TextBox3.Text;    // Body from input

                // Configure SMTP
                SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
                smtp.Credentials = new System.Net.NetworkCredential(
                    "helloeventplanner2025@gmail.com",
                    "lmrpnnsvmdlhexxp" // Gmail App Password
                );
                smtp.EnableSsl = true;

                // Send email
                smtp.Send(mail);

                Label1.Text = "✅ Email sent successfully!";
            }
            catch (Exception ex)
            {
                Label1.Text = "❌ Error: " + ex.Message;
            }
        }
    }
}












<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="smtp1.WebForm1" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            To&nbsp;&nbsp;
            <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
            <br />
            Sub
            <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
            <br />
            Body
            <asp:TextBox ID="TextBox3" runat="server" Height="129px" Width="255px"></asp:TextBox>
            <br />
            <br />
            <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Send" />
        </div>
        <asp:Label ID="Label1" runat="server" Text="Status"></asp:Label>
    </form>
</body>
</html>

Smtp Mail

@final

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net.Mail;



namespace TASK11
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            try
            {
                MailMessage mail = new MailMessage();
                mail.To.Add(TextBox1.Text);
                mail.From = new MailAddress("youremail@domain.com"); // Replace with your email
                mail.Subject = TextBox2.Text;
                mail.Body = TextBox3.Text;

                SmtpClient smtp = new SmtpClient();
                smtp.Host = "smtp.gmail.com"; // Replace with your SMTP server
                smtp.Port = 587; // Replace with SMTP port
                smtp.Credentials = new System.Net.NetworkCredential("username", "password"); // Replace with your credentials
                smtp.EnableSsl = true;
                smtp.Send(mail);
                Label4.Text = "Email sent successfully!";
            }
            catch (Exception ex)
            {
                Label4.Text = "Error: " + ex.Message;
            }
        }
    }
    }

Employee

@final

using System;


class Employee
{
    public string Name { get; set; }
    public int EmployeeID { get; set; }
    public double Salary { get; protected set; }

    public Employee(string name, int id)
    {
        Name = name;
        EmployeeID = id;
    }

    public virtual void DisplayDetails()
    {
        Console.WriteLine("Employee ID: " + EmployeeID);
        Console.WriteLine("Name: " + Name);
        Console.WriteLine("Salary: " + Salary);
    }
}


class FullTimeEmployee : Employee
{
    public double BasicSalary { get; set; }
    public int NumberOfDays { get; set; }
    public double HRA { get; set; }
    public double DA { get; set; }

    public FullTimeEmployee(string name, int id, double basicSalary, int numberOfDays, double hra, double da)
        : base(name, id)
    {
        BasicSalary = basicSalary;
        NumberOfDays = numberOfDays;
        HRA = hra;
        DA = da;
    }

    public void CalculateSalary()
    {
        Salary = (BasicSalary * NumberOfDays) + HRA + DA;
    }

    public override void DisplayDetails()
    {
        base.DisplayDetails();
        Console.WriteLine("Employee Type: Full-Time");
        Console.WriteLine("Basic Salary: " + BasicSalary);
        Console.WriteLine("Number of Days: " + NumberOfDays);
        Console.WriteLine("HRA: " + HRA);
        Console.WriteLine("DA: " + DA);
        Console.WriteLine();
    }
}


class PartTimeEmployee : Employee
{
    public double DailyWages { get; set; }
    public int NumberOfDays { get; set; }

    public PartTimeEmployee(string name, int id, double dailyWages, int numberOfDays)
        : base(name, id)
    {
        DailyWages = dailyWages;
        NumberOfDays = numberOfDays;
    }

    public void CalculateSalary()
    {
        Salary = DailyWages * NumberOfDays;
    }

    public override void DisplayDetails()
    {
        base.DisplayDetails();
        Console.WriteLine("Employee Type: Part-Time");
        Console.WriteLine("Daily Wages: " + DailyWages);
        Console.WriteLine("Number of Days: " + NumberOfDays);
        Console.WriteLine();
    }
}

class Program
{
    static void Main()
    {
        FullTimeEmployee fte = new FullTimeEmployee("Abhi", 101, 1000, 20, 500, 300);
        fte.CalculateSalary();
        fte.DisplayDetails();

        PartTimeEmployee pte = new PartTimeEmployee("Abh", 102, 500, 15);
        pte.CalculateSalary();
        pte.DisplayDetails();
    }
}

Delegates

@final

using System;
using System.Threading;
class Program
{
    public delegate int MathOperation(int a, int b);
    public static int Add(int a, int b)
    {
        Thread.Sleep(2000); 
        return a + b;
    }
    static void Main(string[] args)
    {
        Console.WriteLine("Main Started");
        MathOperation add = Add;
        Console.WriteLine("\nSynchronous call:");
        int syncResult = add(5, 3);
        Console.WriteLine($"Synchronous result: {syncResult}");
        Console.WriteLine("\nAsync call using BeginInvoke:");
        IAsyncResult asyncResult = add.BeginInvoke(20, 20, null, null);
        Console.WriteLine("Main thread continues to run...");
        int asyncResultValue = add.EndInvoke(asyncResult);
        Console.WriteLine($"Asynchronous result: {asyncResultValue}");
        Console.WriteLine("Main Ended");
    }
}

master page

@robo

site1.master 

<!DOCTYPE html>
<html>
<head runat="server">
<title>College Info</title>
</head>
<body>
<form runat="server">
<div style="background-color:lightblue; padding:10px;">
<h1>My College</h1>
<a href="Home.aspx">Home</a> |
<a href="About.aspx">About</a>
</div>
<hr />
<asp:ContentPlaceHolder ID="MainContent" runat="server"></asp:ContentPlaceHolder>
<hr />
<footer>© 2025 My College</footer>
</form>
</body>
</html>

content pages: home
<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
<h2>Welcome to My College</h2>
<p>We offer B.Tech and M.Tech courses in CSE, ECE, and ME.</p>
</asp:Content>

content page: about
<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
<h2>About Our College</h2>
<p>Established in 2001, our college provides quality technical education.</p>
</asp:Content>

smallest digit for a given value

@final

using System;
class Program {
    static void Main() {
        Console.Write("Enter number: ");
        int n = int.Parse(Console.ReadLine());
        int min = 9;
        while(n > 0) {
            int d = n % 10;
            if(d < min) min = d;
            n /= 10;
        }
        Console.WriteLine("Smallest digit: " + min);
    }
}

maximum occurring character in a given string

@final

using System;
using System.Linq;
class Program {
    static void Main() {
        Console.Write("Enter string: ");
        string str = Console.ReadLine();
        var maxChar = str.GroupBy(c => c)
                         .OrderByDescending(g => g.Count())
                         .First().Key;
        Console.WriteLine("Max Occurring: " + maxChar);
    }
}

count the odd numbers in the given number

@final

using System;
class Program {
    static void Main() {
        Console.Write("Enter number: ");
        int n = int.Parse(Console.ReadLine()), count = 0;
        while(n != 0) {
            int d = n % 10;
            if(d % 2 == 1) count++;
            n /= 10;
        }
        Console.WriteLine("Odd digits: " + count);
    }
}

split a substring from a given string

@final

using System;
class Program {
    static void Main() {
        Console.Write("Enter string: ");
        string str = Console.ReadLine();
        Console.Write("Enter start and length: ");
        int start = int.Parse(Console.ReadLine());
        int length = int.Parse(Console.ReadLine());
        string sub = str.Substring(start, length);
        Console.WriteLine("Substring: " + sub);
    }
}

string manipulation using methods of both StringBuilder and String classes

@final

using System;
using System.Text;
class Program {
    static void Main() {
        string str = "hello";
        Console.WriteLine(str.ToUpper());
        Console.WriteLine(str.Replace('l','x'));
        StringBuilder sb = new StringBuilder(str);
        sb.Append(" world");
        Console.WriteLine(sb.ToString());
        sb.Remove(0,2);
        Console.WriteLine(sb);
        sb.Insert(0, "hi ");
        Console.WriteLine(sb);
    }
}

number of vowels in a string

@final

using System;
class Program {
    static void Main() {
        Console.Write("Enter string: ");
        string str = Console.ReadLine();
        int count = str.Count(c => "aeiouAEIOU".Contains(c));
        Console.WriteLine("Vowels: " + count);
    }
}

sum of digits of a number

@final

using System;
class Program {
    static void Main() {
        Console.Write("Enter a number: ");
        int n = int.Parse(Console.ReadLine()), sum = 0;
        while(n > 0) {
            sum += n % 10;
            n /= 10;
        }
        Console.WriteLine("Sum: " + sum);
    }
}

reverse a number

@final

using System;
class Program {
    static void Main() {
        Console.Write("Enter a number: ");
        int n = int.Parse(Console.ReadLine());
        int rev = 0;
        while(n > 0) {
            rev = rev * 10 + n % 10;
            n /= 10;
        }
        Console.WriteLine("Reversed: " + rev);
    }
}

string is a palindrome

@final

using System;
using System.Linq;
class Program {
    static void Main() {
        Console.Write("Enter string: ");
        string str = Console.ReadLine();
        string rev = new string(str.Reverse().ToArray());
        Console.WriteLine(str == rev ? "Palindrome" : "Not palindrome");
    }
}

Fibonacci series up to n terms

@final

using System;
class Program {
    static void Main() {
        Console.Write("Enter terms: ");
        int n = int.Parse(Console.ReadLine());
        int a=0, b=1, c;
        for(int i = 0; i < n; i++) {
            Console.Write(a + " ");
            c = a + b;
            a = b;
            b = c;
        }
    }
}

number is prime

@final

using System;
class Program {
    static void Main() {
        Console.Write("Enter a number: ");
        int n = int.Parse(Console.ReadLine());
        bool isPrime = n > 1;
        for(int i = 2; i <= Math.Sqrt(n); i++) {
            if(n % i == 0) {
                isPrime = false; break;
            }
        }
        Console.WriteLine(isPrime ? "Prime" : "Not prime");
    }
}

#c#

employee master

@vplab2025

Step 1: Create the ASP.NET Web Application

Open Visual Studio → Create New Project → ASP.NET Web Application (.NET Framework).

Name it: EmployeeManagementSystem.

Select Web Forms → Click Create.

Step 2: Create the Master Page

Add → New Item → Master Page → Name: Site1.Master

<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site1.master.cs" Inherits="employee.Site1" %>

<!DOCTYPE html>
<html lang="en">
<head runat="server">
    <title>Employee Management System</title>
    <asp:ContentPlaceHolder ID="head" runat="server"></asp:ContentPlaceHolder>
</head>
<body>
    <form id="form1" runat="server">
        <!-- Header -->
        <div class="header">
            <h1>Employee Management System</h1>
            <nav>
                <a href="Default.aspx">Home</a> |
                <a href="AddEmployee.aspx">Add Employee</a> |
                <a href="ViewEmployee.aspx">View Employee</a>
            </nav>
        </div>

        <!-- Main Content -->
        <asp:ContentPlaceHolder ID="MainContent" runat="server"></asp:ContentPlaceHolder>

        <!-- Footer -->
        <div class="footer">
            <p>&copy; 2025 Employee Management System</p>
        </div>
    </form>
</body>
</html>

Step 3: Create the Home Page

Add → Web Form using Master Page → Name: Default.aspx → Select Site1.Master

<%@ Page Title="Home" Language="C#" MasterPageFile="~/Site1.Master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="employee.Default" %>

<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
    <h2>Welcome to the Home Page</h2>
    <p>Use the menu above to navigate through the Employee Management System.</p>
</asp:Content>

Step 4: Create Add Employee Page

Add → Web Form using Master Page → Name: AddEmployee.aspx → Select Site1.Master

AddEmployee.aspx
<%@ Page Title="Add Employee" Language="C#" MasterPageFile="~/Site1.Master" AutoEventWireup="true" CodeBehind="AddEmployee.aspx.cs" Inherits="employee.AddEmployee" %>

<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
    <h2>Add Employee</h2>

    <asp:TextBox ID="empName" runat="server"></asp:TextBox><br /><br />
    <asp:TextBox ID="position" runat="server"></asp:TextBox><br /><br />
    <asp:TextBox ID="sal" runat="server"></asp:TextBox><br /><br />

    <asp:Button ID="btn" runat="server" Text="Add Employee" OnClick="btn_AddClick" /><br /><br />

    <asp:Label ID="lblMessage" runat="server" Text=""></asp:Label>
</asp:Content>

AddEmployee.aspx.cs
using System;
using System.Collections.Generic;

namespace employee
{
    public partial class AddEmployee : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                empName.Attributes["placeholder"] = "Enter employee name";
                position.Attributes["placeholder"] = "Enter employee position";
                sal.Attributes["placeholder"] = "Enter employee salary";
            }
        }

        protected void btn_AddClick(object sender, EventArgs e)
        {
            string name = empName.Text;
            string pos = position.Text;
            string salary = sal.Text;

            List<Employee> employees = Session["Employees"] as List<Employee> ?? new List<Employee>();
            employees.Add(new Employee { Name = name, Position = pos, Salary = salary });
            Session["Employees"] = employees;

            lblMessage.Text = "Employee added successfully!";

            empName.Text = position.Text = sal.Text = "";
        }
    }

    [Serializable]
    public class Employee
    {
        public string Name { get; set; }
        public string Position { get; set; }
        public string Salary { get; set; }
    }
}

Step 5: Create View Employee Page

Add → Web Form using Master Page → Name: ViewEmployee.aspx → Select Site1.Master

ViewEmployee.aspx
<%@ Page Title="View Employees" Language="C#" MasterPageFile="~/Site1.Master" AutoEventWireup="true" CodeBehind="ViewEmployee.aspx.cs" Inherits="employee.ViewEmployee" %>

<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
    <h2>All Employees</h2>
    <asp:GridView ID="gv" runat="server" AutoGenerateColumns="true"></asp:GridView>
</asp:Content>

ViewEmployee.aspx.cs
using System;
using System.Collections.Generic;

namespace employee
{
    public partial class ViewEmployee : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                List<Employee> employees = Session["Employees"] as List<Employee> ?? new List<Employee>();
                gv.DataSource = employees;
                gv.DataBind();
            }
        }
    }
}

#c#

web form registration

@vplab2025

WebForm1.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="userreg.WebForm1" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>User Registration</title>
    <style>
        .error { color: red; }
        .form-field { margin-bottom: 10px; }
    </style>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <h2>Registration Form</h2>

            <div class="form-field">
                Name: 
                <asp:TextBox ID="txtName" runat="server" AutoPostBack="true" OnTextChanged="txtName_TextChanged"></asp:TextBox>
                <asp:RequiredFieldValidator ID="rfvName" runat="server" 
                    ControlToValidate="txtName" ErrorMessage="Name is required" CssClass="error"></asp:RequiredFieldValidator>
            </div>

            <div class="form-field">
                Age:
                <asp:TextBox ID="txtAge" runat="server"></asp:TextBox>
                <asp:RequiredFieldValidator ID="rfvAge" runat="server"
                    ControlToValidate="txtAge" ErrorMessage="Age is required" CssClass="error"></asp:RequiredFieldValidator>
                <asp:RangeValidator ID="rvAge" runat="server" 
                    ControlToValidate="txtAge" MinimumValue="20" MaximumValue="30" Type="Integer" 
                    ErrorMessage="Age must be between 20 and 30" CssClass="error"></asp:RangeValidator>
            </div>

            <div class="form-field">
                Email ID:
                <asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>
                <asp:RequiredFieldValidator ID="rfvEmail" runat="server"
                    ControlToValidate="txtEmail" ErrorMessage="Email is required" CssClass="error"></asp:RequiredFieldValidator>
                <asp:RegularExpressionValidator ID="revEmail" runat="server"
                    ControlToValidate="txtEmail"
                    ErrorMessage="Invalid Email"
                    ValidationExpression="^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$"
                    CssClass="error">
                </asp:RegularExpressionValidator>
            </div>

            <div class="form-field">
                User ID:
                <asp:TextBox ID="txtUserID" runat="server"></asp:TextBox>
                <asp:RequiredFieldValidator ID="rfvUserID" runat="server"
                    ControlToValidate="txtUserID" ErrorMessage="UserID is required" CssClass="error"></asp:RequiredFieldValidator>
                <asp:RegularExpressionValidator ID="revUserID" runat="server"
                    ControlToValidate="txtUserID"
                    ErrorMessage="UserID must contain a capital letter and a digit, 7-20 chars"
                    ValidationExpression="^(?=.*[A-Z])(?=.*\d).{7,20}$"
                    CssClass="error">
                </asp:RegularExpressionValidator>
            </div>

            <div class="form-field">
                Password:
                <asp:TextBox ID="txtPassword" runat="server" TextMode="Password"></asp:TextBox>
                <asp:RequiredFieldValidator ID="rfvPassword" runat="server"
                    ControlToValidate="txtPassword" ErrorMessage="Password is required" CssClass="error"></asp:RequiredFieldValidator>
                <asp:RegularExpressionValidator ID="revPassword" runat="server"
                    ControlToValidate="txtPassword"
                    ErrorMessage="Password must be 7-20 chars"
                    ValidationExpression="^.{7,20}$"
                    CssClass="error">
                </asp:RegularExpressionValidator>
            </div>

            <div class="form-field">
                <asp:Button ID="btnSubmit" runat="server" Text="Register" OnClick="btnSubmit_Click" />
            </div>

            <asp:Label ID="lblMessage" runat="server" ForeColor="Green"></asp:Label>

        </div>
    </form>
</body>
</html>




WebForm1.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace userreg
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            UnobtrusiveValidationMode = UnobtrusiveValidationMode.None;
        }

        protected void txtName_TextChanged(object sender, EventArgs e)
        {

        }

        protected void btnSubmit_Click(object sender, EventArgs e)
        {
            if (Page.IsValid)
            {
                lblMessage.Text = "Registration Successful!";
                // Optional: Save data to database here
            }
        }
    }
}




Steps:

1. Choose ASP.NET Web Application (.NET Framework)
2. Choose empty and Check the Web Forms
3. Right click on solution explorer and add a new item web forms and edit the codes and paste the above 2 codes
4. make sure to right click on webform1.aspx and click set as start page
5. click run

#c#

upload and download

@vplab2025

Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            using (WebClient client = new WebClient())
            {
                string url = textBox1.Text;
                string filePath = @"C:\Users\Koyya\OneDrive\Desktop\example.txt";

                client.DownloadFile(url, filePath);

                MessageBox.Show("dome");


            }
        }
    }
}

========================



Steps

1. Create a new project using Windows Forms App (.NET Framework)
2.Add Controls to the Form using ToolBox

	TextBox → for entering URL (textBox1)

	Button → for DOWNLOAD (buttonDownload)

	Button → for UPLOAD (button1)

	Label → to show status (label1)


3. Double click on both the buttons and paste the above functions in those functions of respective buttons

#c#

Master Page

@vplab2025

Step - 1

=====================

Site1.Master

<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site1.master.cs" Inherits="StudentApplication.Site1" %>

<!DOCTYPE html>
<html>
<head runat="server">
    <title>College Information</title>
    <link rel="stylesheet" href="style.css" />
    <asp:ContentPlaceHolder ID="head" runat="server">
    </asp:ContentPlaceHolder>
</head>
<body>
    <form id="form1" runat="server">
        <!-- Header -->
        <header style="background-color:#f5f5f5; padding:20px; text-align:center;">
            <h1>CVR College of Engineering</h1>
        </header>

        <!-- Menu -->
        <asp:Menu ID="menu1" runat="server" Orientation="Horizontal">
            <Items>
                <asp:MenuItem NavigateUrl="~/Home.aspx" Text="HOME" Value="HOME" />
            </Items>
        </asp:Menu>

        <!-- College Image -->
        <div style="text-align:center; margin:20px;">
            <asp:Image ID="Image1" runat="server" ImageUrl="~/Images/cur.jpg" Width="50%" />
        </div>

        <!-- Content Area -->
        <div class="content-area" style="margin:20px;">
            <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server" />
        </div>

        <!-- Footer -->
        <footer style="background-color:#eee; text-align:center; padding:15px; font-size:12px;">
            © 2025 Student Management System. All rights reserved
        </footer>
    </form>
</body>
</html>


==================

WebForm1.aspx

<%@ Page Title="Home" Language="C#" MasterPageFile="~/Site1.Master" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="StudentApplication.WebForm1" %>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
    <h2>Welcome to CVR College of Engineering</h2>
    <p>This student management system helps in managing student records efficiently.</p>
</asp:Content>

===================


Steps:

1. Select ASP.NET Web Application(.NET Framework) with C#
2. Name it StudentApplication
3. Click Create and select empty and tick WebForms checkbox
4. Click Create
5. Right click on solution explorer and click add -> new item -> web forms master page -> add
6. Paste the above Site1.Master code in it
7. Right click on solution explorer and click add -> new item -> web forms with master page -> add -> site1.master -> ok
8. paste the above WebForm1.aspx code in it
9. Right click on WebForm1.aspx in solution explorer and click set as start page
10. Run the code


=====================

Note: If you set another name to your project, change it in the first line of Inherits attribute

file upload and download

@rcb

 using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsAppFinal
{
    public partial class Form1 : Form
    {
        WebClient client = new WebClient();

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                string url = textBox1.Text.Trim();
                if (string.IsNullOrEmpty(url))
                {
                    label1.Text = "Please enter a download URL.";
                    return;
                }

                string savePath = "C:\\Users\\AKHILESH\\OneDrive\\Desktop\\download.txt";


                client.DownloadFile(url, savePath);
                label1.Text = "File downloaded to " + savePath;
            }
            catch (Exception ex)
            {
                label2.Text = "Error: " + ex.Message;
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            try
            {
                string url = textBox2.Text; // Example: https://httpbin.org/post
                string filePath = "C:\\Users\\AKHILESH\\OneDrive\\Desktop\\dummy.txt";

                client.UploadFile(url, "POST", filePath);
                MessageBox.Show("File uploaded successfully!");


                label2.Text = "Upload completed";
            }
            catch (Exception ex)
            {
                label2.Text = "Error: " + ex.Message;
            }
        }
    }

}
 
        https://raw.githubusercontent.com/vinta/awesome-python/master/README.md
https://httpbin.org/post

#c#

Delegate

@vplab2025

using System;

namespace practice
{
    public delegate int MathOperation(int x, int y);

    public class DelegateExample
    {
        public static int Add(int x, int y)
        {
            return x + y;
        }

        public static void Main()
        {
            MathOperation d = Add;
            int res = d(2, 3);
            Console.WriteLine("Result: "+res);
        }
    }
}

#c#

Explicit Interface Inheritance

@vplab2025

using System;

namespace practice
{
    interface IEmployee
    {
        void empdisplaydetails();
    }

    interface IManager : IEmployee
    {
        void Managerdetails();
    }

    class Departmentdetails : IManager
    {
        void IEmployee.empdisplaydetails()
        {
            Console.WriteLine("Employee Details");
        }

        void IManager.Managerdetails()
        {
            Console.WriteLine("Manager is working in sales department");
        }
    }

    class Program
    {
        public static void Main(string[] args)
        {
            Departmentdetails d = new Departmentdetails();

            IEmployee emp = d;
            emp.empdisplaydetails();

            IManager mg = d;
            mg.Managerdetails();
        }
    }
}

#c#

Email Match

@vplab2025

using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
        Console.Write("Enter an email: ");
        string email = Console.ReadLine();

        string pattern = @"^[^@\s]+@[^@\s]+\.[^@\s]+$";

        if (Regex.IsMatch(email, pattern))
            Console.WriteLine("Email is in proper format.");
        else
            Console.WriteLine("Email is NOT in proper format.");
    }
}

#c#

Private Assembly

@vplab2025

//Step 1: Create the Private Assembly (Class Library)

//Open Visual Studio → Create a new project → select Class Library (.NET Framework).

//Name it: MyMathLibrary.

//Replace the default class code with:

using System;

namespace MyMathLibrary
{
    public class MathOperations
    {
        public int Add(int a, int b)
        {
            return a + b;
        }

        public int Multiply(int a, int b)
        {
            return a * b;
        }
    }
}


//Build the project → This generates MyMathLibrary.dll in bin\Debug\net6.0\.

//Step 2: Create the Console Application

//Open Visual Studio → Create a new project → Console App.

//Name it: UseMyMathLibrary.

//Step 3: Add Reference via Dependencies

//In Solution Explorer, expand the console app project (UseMyMathLibrary).

//Right-click Dependencies → Add Project Reference -> Browse -> MyMathLibrary->bin->Debug->.dll

//Check MyMathLibrary → click OK


//Step 4: Use the Assembly in Your Console App
using System;
using MyMathLibrary;

class Program
{
    static void Main()
    {
        MathOperations math = new MathOperations();

        int sum = math.Add(10, 20);
        int product = math.Multiply(5, 4);

        Console.WriteLine("Sum: " + sum);
        Console.WriteLine("Product: " + product);
    }
}

#c#

Smallest Digit

@vplab2025

using System;

class Program
{
    static void Main()
    {
        Console.Write("Enter a number: ");
        int num = Convert.ToInt32(Console.ReadLine());

        int smallest = 9;

        while (num > 0)
        {
            int digit = num % 10;
            if (digit < smallest)
                smallest = digit;
            num /= 10;
        }

        Console.WriteLine("Smallest digit: " + smallest);
    }
}

#c#

Highest Frequency

@vplab2025

using System;

class Program
{
    static void Main()
    {
        Console.Write("Enter a string: ");
        string str = Console.ReadLine().ToLower();

        int[] freq = new int[256]; 

        foreach (char ch in str)
        {
            if (ch != ' ')
                freq[ch]++;
        }

        int max = 0;
        char maxChar = ' ';

        for (int i = 0; i < 256; i++)
        {
            if (freq[i] > max)
            {
                max = freq[i];
                maxChar = (char)i;
            }
        }

        Console.WriteLine("Maximum occurring character: " + maxChar);
        Console.WriteLine("Occurrences: " + max);
    }
}

college site

@rcb

//Site1.Master
 <style>
     body {
         font-family: Arial, sans-serif;
         margin: 0;
         padding: 0;
     }

     header {
         background-color: #003366;
         color: white;
         padding: 15px;
         text-align: center;
         font-size: 24px;
     }

     nav {
         background-color: #005599;
         overflow: hidden;
     }

     nav a {
         float: left;
         display: block;
         color: white;
         text-align: center;
         padding: 14px 20px;
         text-decoration: none;
     }

     nav a:hover {
         background-color: #003366;
     }

     footer {
         background-color: #003366;
         color: white;
         text-align: center;
         padding: 10px;
         position: fixed;
         bottom: 0;
         width: 100%;
     }

     .content {
         padding: 20px;
         margin-bottom: 60px; /* space for footer */
     }
 </style>

//inside form tag
 <header>
     Welcome to ABC College of Engineering
 </header>

 <nav>
     <a href="Home.aspx">Home</a>
     <a href="Aboutus.aspx">About</a>
     
     <a href="Contactus.aspx">Contact</a>
 </nav>

 <div class="content">
     <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
     </asp:ContentPlaceHolder>
 </div>

 <footer>
     &copy; 2025 ABC College | All Rights Reserved
 </footer>
//Aboutus.apsx
    <h2>About Our College</h2>
<p>Founded in 1990, ABC College of Engineering is one of the premier institutions offering quality education.</p>
<p>Our mission is to produce skilled engineers and leaders capable of addressing global challenges.</p>
//similarly Contactus.aspx

#c#

Substring

@vplab2025

using System;

class Program
{
    static void Main()
    {
        Console.Write("Enter a string: ");
        string str = Console.ReadLine();

        Console.Write("Enter the starting index: ");
        int start = Convert.ToInt32(Console.ReadLine());

        Console.Write("Enter the length of substring: ");
        int length = Convert.ToInt32(Console.ReadLine());

        string sub = str.Substring(start, length);

        Console.WriteLine("Extracted Substring: " + sub);
    }
}

#c#

String Methods and StringBuilder Methods

@vplab2025

using System;
using System.Text; // Required for StringBuilder

class Program
{
    static void Main()
    {
        // --- String Class Methods ---
        Console.WriteLine("=== String Class Methods ===");
        string str = "Hello World";

        Console.WriteLine("Original String: " + str);
        Console.WriteLine("To Upper Case: " + str.ToUpper());
        Console.WriteLine("To Lower Case: " + str.ToLower());
        Console.WriteLine("Substring (0,5): " + str.Substring(0, 5));
        Console.WriteLine("Replaced 'World' with 'C#': " + str.Replace("World", "C#"));
        Console.WriteLine("Contains 'Hello'? " + str.Contains("Hello"));
        Console.WriteLine("Length: " + str.Length);

        // --- StringBuilder Class Methods ---
        Console.WriteLine("\n=== StringBuilder Class Methods ===");
        StringBuilder sb = new StringBuilder("Hello");

        sb.Append(" World");
        Console.WriteLine("After Append: " + sb);

        sb.Insert(5, " C#");
        Console.WriteLine("After Insert: " + sb);

        sb.Replace("World", "Developers");
        Console.WriteLine("After Replace: " + sb);

        sb.Remove(5, 3);
        Console.WriteLine("After Remove: " + sb);

        sb.Clear();
        sb.Append("New String");
        Console.WriteLine("After Clear and Append: " + sb);
    }
}

#c#

Vowels

@vplab2025

using System;

class Program
{
    static void Main()
    {
        Console.Write("Enter a string: ");
        string str = Console.ReadLine().ToLower();

        int count = 0;

        foreach (char ch in str)
        {
            if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u')
            {
                count++;
            }
        }

        Console.WriteLine("Number of vowels: " + count);
    }
}

#c#

Sum of Digits

@vplab2025

class Program
{
    static void Main()
    {
        Console.WriteLine("Enter a Number: ");
        int num = Convert.ToInt32(Console.ReadLine());

        int sum = 0;

        while (num > 0)
        {
            int digit = num % 10;
            sum += digit;
            num /= 10;
        }

        Console.WriteLine("Sum of digits: " + sum);

    }
}

#c#

Reverse of a number

@vplab2025

class Program
{
    static void Main()
    {
        Console.WriteLine("Enter a Number: ");
        int num = Convert.ToInt32(Console.ReadLine());

        int reversed = 0;

        while (num > 0)
        {
            int digit = num % 10;
            reversed = reversed * 10 + digit;
            num /= 10;
        }

        Console.WriteLine("Reversed Num: " + reversed);

    }
}

smallest digit

@robo

using System;
class SmallestDigit
{
    static void Main()
    {
        Console.Write("Enter a number: ");
        int num = Convert.ToInt32(Console.ReadLine());
        int smallest = 9;

        while (num > 0)
        {
            int digit = num % 10;
            if (digit < smallest)
                smallest = digit;
            num /= 10;
        }

        Console.WriteLine("Smallest digit: " + smallest);
    }
}

max occuring char in a string

@robo

using System;
class MaxOccurringChar
{
    static void Main()
    {
        Console.Write("Enter a string: ");
        string str = Console.ReadLine();
        int[] freq = new int[256];

        foreach (char c in str)
            freq[c]++;

        int max = 0;
        char result = ' ';

        foreach (char c in str)
        {
            if (freq[c] > max)
            {
                max = freq[c];
                result = c;
            }
        }

        Console.WriteLine($"Maximum occurring character: {result}");
    }
}

#c#

Palindrome

@vplab2025

class Program
{
    static void Main()
    {
        Console.WriteLine("Enter a String: ");
        string str = Console.ReadLine();

        string reversed = "";
        
        for(int i = str.Length - 1; i >= 0; i--)
        {
            reversed += str[i];
        }

        Boolean equal = true;

        for(int i = 0; i < str.Length; i++)
        {
            if (!(str[i] == reversed[i]))
            {
                equal = false; break;
            }
        }

        Console.WriteLine(equal ? "String is Palindrome" : "String is not a Palindrome");

    }
}

count no of odd digits

@robo

using System;
class CountOddDigits
{
    static void Main()
    {
        Console.Write("Enter a number: ");
        int num = Convert.ToInt32(Console.ReadLine());
        int count = 0;

        while (num > 0)
        {
            int digit = num % 10;
            if (digit % 2 != 0)
                count++;
            num /= 10;
        }

        Console.WriteLine("Count of odd digits: " + count);
    }
}

split into substring

@robo

using System;
class Program {
    static void Main() {
        Console.Write("Enter string: ");
        string str = Console.ReadLine();
        Console.Write("Enter start and length: ");
        int start = int.Parse(Console.ReadLine());
        int length = int.Parse(Console.ReadLine());
        string sub = str.Substring(start, length);
        Console.WriteLine("Substring: " + sub);
    }
}

string manipulation and sb

@robo

using System;
using System.Text;
class StringManipulation
{
    static void Main()
    {
        string s = "Hello";
        Console.WriteLine("Original String: " + s);
        s = s.ToUpper();
        Console.WriteLine("Uppercase: " + s);
        s = s.Replace("HELLO", "WORLD");
        Console.WriteLine("Replaced: " + s);

        // StringBuilder
        StringBuilder sb = new StringBuilder("Welcome");
        sb.Append(" to C#");
        Console.WriteLine("StringBuilder Append: " + sb);
        sb.Insert(0, "Hi! ");
        Console.WriteLine("After Insert: " + sb);
        sb.Replace("C#", "Programming");
        Console.WriteLine("After Replace: " + sb);
    }
}

count of vowels

@robo

using System;
class Program {
    static void Main() {
        Console.Write("Enter string: ");
        string str = Console.ReadLine();
        int count = str.Count(c => "aeiouAEIOU".Contains(c));
        Console.WriteLine("Vowels: " + count);
    }
}

sum of digits

@robo

using System;
class SumOfDigits
{
    static void Main()
    {
        Console.Write("Enter a number: ");
        int num = Convert.ToInt32(Console.ReadLine());
        int sum = 0;

        while (num > 0)
        {
            sum += num % 10;
            num /= 10;
        }

        Console.WriteLine("Sum of digits: " + sum);
    }
}

rev of num

@robo

using System;
class ReverseNumber
{
    static void Main()
    {
        Console.Write("Enter a number: ");
        int num = Convert.ToInt32(Console.ReadLine());
        int rev = 0;

        while (num > 0)
        {
            rev = rev * 10 + num % 10;
            num = num / 10;
        }

        Console.WriteLine("Reversed Number: " + rev);
    }
}

Palindrome

@robo

using System;
using System.Linq;
class Program {
    static void Main() {
        Console.Write("Enter string: ");
        string str = Console.ReadLine();
        string rev = new string(str.Reverse().ToArray());
        Console.WriteLine(str == rev ? "Palindrome" : "Not palindrome");
    }
}

or 

using System;
class Palindrome
{
    static void Main()
    {
        Console.Write("Enter a string: ");
        string str = Console.ReadLine();
        string rev = "";

        for (int i = str.Length - 1; i >= 0; i--)
            rev += str[i];

        if (str == rev)
            Console.WriteLine("Palindrome");
        else
            Console.WriteLine("Not Palindrome");
    }
}

#c#

Fibonacci

@vplab2025

class Program
{
    static void Main()
    {
        Console.WriteLine("Enter a number: ");
        int N = Convert.ToInt32(Console.ReadLine());

        int first = 0;
        int second = 1;

        Console.WriteLine("Fibonacci Series");

        for(int i = 1; i <= N; i++)
        {
            Console.Write(first + " ");
            int next = first + second;
            first = second;
            second = next;
        }

    }
}

Fibonacci

@robo

using System;
class Fibonacci
{
    static void Main()
    {
        Console.Write("Enter the number of terms: ");
        int n = Convert.ToInt32(Console.ReadLine());
        int a = 0, b = 1, c;

        Console.Write("Fibonacci Series: ");
        for (int i = 1; i <= n; i++)
        {
            Console.Write(a + " ");
            c = a + b;
            a = b;
            b = c;
        }
    }
}

Prime

@robo

using System;
class Program {
    static void Main() {
        Console.Write("Enter a number: ");
        int n = int.Parse(Console.ReadLine());
        bool isPrime = n > 1;
        for(int i = 2; i <= Math.Sqrt(n); i++) {
            if(n % i == 0) {
                isPrime = false; break;
            }
        }
        Console.WriteLine(isPrime ? "Prime" : "Not prime");
    }
}

#c#

Prime or Not

@vplab2025

class Program
{
    static void Main()
    {
        Console.WriteLine("Enter a number: ");
        int num = Convert.ToInt32(Console.ReadLine());
        if (IsPrime(num))
        {
            Console.WriteLine("Prime Number");
        }
        else
        {
            Console.WriteLine("Not a Prime Number");
        }
    }

    static Boolean IsPrime(int num)
    {
        if (num == 1 || num == 0) return false;
        int c = 0;
        for(int i = 1; i <= num; i++)
        {
            if(num%i == 0)
            {
                c++;
            }
        }

        return c == 2;
    }
}

fte,pte

@rcb

using System;

// Base class
class Employee
{
    public string Name { get; set; }
    public int EmployeeID { get; set; }
    public double Salary { get; set; }

    public Employee(string name, int id)
    {
        Name = name;
        EmployeeID = id;
    }

    // Virtual method to be overridden in derived classes
    public virtual void CalculateSalary()
    {
        Salary = 0;
    }

    public void Display()
    {
        Console.WriteLine("Employee Name: " + Name);
        Console.WriteLine("Employee ID: " + EmployeeID);
        Console.WriteLine("Salary: " + Salary);
        Console.WriteLine("-----------------------------");
    }
}

// Derived class: FullTimeEmployee
class FullTimeEmployee : Employee
{
    public double BasicSalary { get; set; }
    public int NumberOfDays { get; set; }
    public double HRA { get; set; }
    public double DA { get; set; }

    public FullTimeEmployee(string name, int id, double basic, int days, double hra, double da)
        : base(name, id)
    {
        BasicSalary = basic;
        NumberOfDays = days;
        HRA = hra;
        DA = da;
    }

    public override void CalculateSalary()
    {
        Salary = (BasicSalary * NumberOfDays) + HRA + DA;
    }
}

// Derived class: PartTimeEmployee
class PartTimeEmployee : Employee
{
    public double DailyWages { get; set; }
    public int NumberOfDays { get; set; }

    public PartTimeEmployee(string name, int id, double wages, int days)
        : base(name, id)
    {
        DailyWages = wages;
        NumberOfDays = days;
    }

    public override void CalculateSalary()
    {
        Salary = DailyWages * NumberOfDays;
    }
}

// Main Program
class Program
{
    static void Main()
    {
        // Create Full-Time Employee
        FullTimeEmployee fte = new FullTimeEmployee("Alice", 101, 1000, 22, 500, 300);
        fte.CalculateSalary();
        fte.Display();

        // Create Part-Time Employee
        PartTimeEmployee pte = new PartTimeEmployee("Bob", 102, 500, 15);
        pte.CalculateSalary();
        pte.Display();

        Console.ReadLine();
    }
}

explicit interface implemenation

@rcb

using System;

// Step 1: Base interface
interface IShape
{
    void Draw();
}

// Step 2: Derived interface inherits from IShape
interface IColorShape : IShape
{
    void FillColor();
}

// Step 3: Implement the derived interface explicitly
class Rectangle : IColorShape
{
    // Explicit implementation of Draw() from IShape
    void IShape.Draw()
    {
        Console.WriteLine("Drawing a Rectangle");
    }

    // Explicit implementation of FillColor() from IColorShape
    void IColorShape.FillColor()
    {
        Console.WriteLine("Filling Rectangle with Blue color");
    }
}

class Program
{
    static void Main()
    {
        // Create object of Rectangle
        Rectangle rect = new Rectangle();

        // To access explicit interface methods, we need to cast to interface
        IShape shape = rect;
        shape.Draw();  // Calls IShape.Draw()

        IColorShape colorShape = rect;
        colorShape.FillColor();  // Calls IColorShape.FillColor()

        Console.ReadLine();
    }
}

delegate

@rcb

 public delegate void OperationOnDelegate(int x,int y);
 internal class Program
 {
     public static void Add(int x,int y)
     {
         Console.WriteLine($"Add:{x + y}");

     }

     public static void Sub(int x, int y)
     {
         Console.WriteLine($"Sub:{x - y}");


     }

     public static void Mul(int x, int y)
     {
         Console.WriteLine($"Sub:{x * y}");
     }




     static void Main(string[] args)
     {
         OperationOnDelegate op;
         op = Add;
         op(10, 20);
         op = Sub;
         op(10, 20);
         op = Mul;
         op(10, 20);
         op = Add;
         op += Sub;
         op += Mul;
         op(20, 10);
     }
 }

smtp

Smtp Mail

Employee

Delegates

master page

smallest digit for a given value

maximum occurring character in a given string

count the odd numbers in the given number

split a substring from a given string

string manipulation using methods of both StringBuilder and String classes

number of vowels in a string

sum of digits of a number

reverse a number

string is a palindrome

Fibonacci series up to n terms

number is prime

employee master

web form registration

upload and download

Master Page

file upload and download

Delegate

Explicit Interface Inheritance

Email Match

Private Assembly

Smallest Digit

Highest Frequency

college site

Substring

String Methods and StringBuilder Methods

Vowels

Sum of Digits

Reverse of a number

smallest digit

max occuring char in a string

Palindrome

count no of odd digits

split into substring

string manipulation and sb

count of vowels

sum of digits

rev of num

Palindrome

Fibonacci

Fibonacci

Prime

Prime or Not

fte,pte

explicit interface implemenation

delegate

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