General  

Print Right Triangle Star Pattern using C# in ASP.NET WebForms

Introduction

Pattern printing is a popular programming exercise used to understand loops, nested iterations, and logic control in programming.
In this article, you’ll learn how to print a right triangle star pattern using C# WebForms (Visual Studio 2015) — a real-time example that helps you understand nested loop structures.

Pattern to Print

If the user enters 5, the output should be:

*
* *
* * *
* * * *
* * * * *

C# WebForms Real-Time Example

ASPX Page (RightTriangle.aspx)

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

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Right Triangle Star Pattern</title>
</head>
<body>
    <form id="form1" runat="server">
        <div style="font-family: Arial; margin: 50px;">
            <h2>Right Triangle Star Pattern</h2>
            <asp:Label ID="Label1" runat="server" Text="Enter number of rows: " />
            <asp:TextBox ID="txtRows" runat="server"></asp:TextBox>
            <asp:Button ID="btnPrint" runat="server" Text="Print Pattern" OnClick="btnPrint_Click" />
            <br /><br />
            <asp:Label ID="lblResult" runat="server" Font-Names="Consolas" Font-Size="Large"></asp:Label>
        </div>
    </form>
</body>
</html>

Code-Behind (RightTriangle.aspx.cs)

using System;
using System.Text;

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

        protected void btnPrint_Click(object sender, EventArgs e)
        {
            int rows;
            if (int.TryParse(txtRows.Text, out rows) && rows > 0)
            {
                lblResult.Text = GenerateTriangle(rows);
            }
            else
            {
                lblResult.Text = "Please enter a valid positive number.";
            }
        }

        private string GenerateTriangle(int rows)
        {
            StringBuilder pattern = new StringBuilder();

            for (int i = 1; i <= rows; i++)
            {
                for (int j = 1; j <= i; j++)
                {
                    pattern.Append("* ");
                }
                pattern.Append("<br/>");
            }

            return pattern.ToString();
        }
    }
}

Explanation

  1. The user enters the number of rows in the text box.

  2. When the “Print Pattern” button is clicked:

    • The program reads the number.

    • Calls the GenerateTriangle() method.

  3. Nested loops are used:

    • Outer loop (i) → controls number of rows.

    • Inner loop (j) → prints stars in each row.

  4. <br/> is used for line breaks in the web output.

Example Output

For input 5

*
* *
* * *
* * * *
* * * * *

Key Concepts

  • Nested Loops → Used for pattern control.

  • StringBuilder → Efficient for string concatenation.

  • WebForms Output → Line breaks handled using <br/> tag.

Real-Time Use Case

  • Used in training portals, online coding platforms, or educational web apps.

  • Helps beginners visualize how nested loops work in C# Web Applications.

Conclusion

This simple yet effective example demonstrates how nested loops work in C# WebForms to generate a right triangle star pattern dynamically.

It strengthens understanding of loops, logic, and dynamic HTML output in ASP.NET WebForms.

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