Rearrange an array in order – largest,smallest, 2nd largest , 2nd smallest,... nth largest, nth smallest

Input is Array of integers. task is to check if any duplicates is there need to print like "Invalid Input". if duplicates not there we need to print like.

1st Largest Number, 1st smallest number, 2nd largest number, 2nd smallest number,....nth largest number, nth smallest..

You can see Examples in below:

Example 1: 

 Input: arr[] = [5, 8, 1, 4, 2,2, 9, 3, 7, 6]

 Output: Invalid Input

Example 2: 

Input: arr[] = [1,3,4,2,5,7,9,8,6]

Output:

9

1

8

2

7

3

6

4

5

Solution in C#.net

using System;

using System.Linq;

namespace ConsoleApp4

{

    class Program

    {

        static void Main(string[] args)

        {

            int[] input1 = new int[] { 1, 2, 3, 4, 5, 7, 8, 9, 6 };

            BigAndSmallNumbers(input1);

            Console.ReadKey();

        }

        public static void BigAndSmallNumbers(int[] input1)

        {

            bool duplicate = false;

            for (int i = 0; i < input1.Length; i++)

            {

                for (int j = i + 1; j < input1.Length; j++)

                {

                    if (input1[i] == input1[j])

                    {

                        duplicate = true;

                    }

                }

            }

            if (duplicate == false)

            {

                Array.Sort(input1);

                Array.Reverse(input1);

                int n = input1.Length;

                int ArrIndex = 0;

                int[] output = new int[input1.Length];

                for (int i = 0, j = n - 1; i <= n / 2 || j > n / 2; i++, j--)

                {

                    if (ArrIndex < n)

                    {

                        output[ArrIndex] = input1[i];

                        ArrIndex++;

                    }

                    if (ArrIndex < n)

                    {

                        output[ArrIndex] = input1[j];

                        ArrIndex++;

                    }

                }

                foreach (var a in output)

                {

                    Console.WriteLine(a);

                }

            }

            else

            {

                Console.WriteLine("Invalid Input");

            }

        }

    }

}

Code in Git: 

https://github.com/adi501/Rearrange-an-array-in-order-largest-smallest-2nd-largest-2nd-smallest-...-nth-largest-nth-smal

tab delimited text file writing and reading in c#

 

using System;

using System.IO;

using System.Text;

namespace tab_delimited

{

    class Program

    {

        static void Main(string[] args)

        {

            string fileName = @"C:\Temp\Adi.txt";

            try

            {

                // Check if file already exists. If yes, delete it.     

                if (File.Exists(fileName))

                {

                    File.Delete(fileName);

                }

                var delimiter = "\t";

                var newline = "\n";

                StringBuilder sb = new StringBuilder();

                sb.Append("1" + delimiter + "2" + delimiter + "3" + delimiter + "4" + delimiter + "5");

                sb.Append(newline);

                sb.Append("6" + delimiter + "7" + delimiter + "8" + delimiter + "9" + delimiter + "10");

                sb.Append(newline);

                sb.Append("11" + delimiter + "12" + delimiter + "13" + delimiter + "14" + delimiter + "15");

                sb.Append(newline);

                sb.Append("16" + delimiter + "17" + delimiter + "18" + delimiter + "19" + delimiter + "20");

                // Create a new file     

                using (FileStream fs = File.Create(fileName))

                {

                    //// Add some text to file    

                    Byte[] title = new UTF8Encoding(true).GetBytes(sb.ToString());

                    fs.Write(title, 0, title.Length);

                }

                // Open the stream and read it back.    

                using (StreamReader sr = File.OpenText(fileName))

                {

                    string s = "";

                    while ((s = sr.ReadLine()) != null)

                    {

                        Console.WriteLine(s);

                    }

                }

                Console.ReadLine();

            }

            catch (Exception Ex)

            {

                Console.WriteLine(Ex.ToString());

            }

        }

    }

}

Output:

Find all possible combinations of numbers in c#

Code:

using System;
using System.Collections.Generic; namespace All_Possible_Combinations_of_a_number { class Program { static void Main(string[] args) { Console.WriteLine("Enter a Number:"); int number = Convert.ToInt32(Console.ReadLine()); List<int> listNumbers = new List<int>(); for (int i=1;i<=number;i++) { listNumbers.Add(i); } Console.WriteLine("Output:"); double count = Math.Pow(2, listNumbers.Count); for (int i = 1; i <= count - 1; i++) { string aa = ""; for (int j = 0; j < listNumbers.Count; j++) { int b = i & (1 << j); if (b > 0) { aa = aa + listNumbers[j]; } } Console.WriteLine(aa); } Console.ReadLine(); } } }

Output:

Sort numbers based on last digit in c#

Code:

using System; using System.Collections.Generic; using System.Linq; namespace Sort_numbers_based_on_last_digit { class Program { static void Main(string[] args) { List<MyNumbers> listMyNumbers = new List<MyNumbers>(); listMyNumbers.Add(new MyNumbers { Number = 13 }); listMyNumbers.Add(new MyNumbers { Number = 23 }); listMyNumbers.Add(new MyNumbers { Number = 123 }); listMyNumbers.Add(new MyNumbers { Number = 4 }); listMyNumbers.Add(new MyNumbers { Number = 345 }); listMyNumbers.Add(new MyNumbers { Number = 1235 }); listMyNumbers.Add(new MyNumbers { Number = 2345 }); listMyNumbers.Add(new MyNumbers { Number = 12345 }); listMyNumbers.Add(new MyNumbers { Number = 1 }); listMyNumbers.Add(new MyNumbers { Number = 2 }); listMyNumbers.Add(new MyNumbers { Number = 14 }); listMyNumbers.Add(new MyNumbers { Number = 24 }); listMyNumbers.Add(new MyNumbers { Number = 34 }); listMyNumbers.Add(new MyNumbers { Number = 124 }); listMyNumbers.Add(new MyNumbers { Number = 234 }); listMyNumbers.Add(new MyNumbers { Number = 1234 }); listMyNumbers.Add(new MyNumbers { Number = 5 }); listMyNumbers.Add(new MyNumbers { Number = 15 }); listMyNumbers.Add(new MyNumbers { Number = 25 }); listMyNumbers.Add(new MyNumbers { Number = 35 }); listMyNumbers.Add(new MyNumbers { Number = 45 }); listMyNumbers.Add(new MyNumbers { Number = 125 }); listMyNumbers.Add(new MyNumbers { Number = 12 }); listMyNumbers.Add(new MyNumbers { Number = 3 }); listMyNumbers.Add(new MyNumbers { Number = 235 }); List<MyNumbers> listMyNumbers1 = new List<MyNumbers>(); foreach (var a in listMyNumbers) { MyNumbers obj = new MyNumbers(); obj.Number = a.Number; obj.LastNumber= Math.Abs(a.Number) % 10; obj.TotalCount = (a.Number).ToString().Length; listMyNumbers1.Add(obj); } List<MyNumbers> listMyNumbers2 = listMyNumbers1.OrderBy(x => x.LastNumber).ThenBy(x=>x.TotalCount).ToList(); Console.WriteLine("Input:"); foreach(var a in listMyNumbers) { Console.WriteLine(a.Number); } Console.WriteLine("Output:"); foreach (var a in listMyNumbers2) { Console.WriteLine(a.Number); } Console.ReadLine(); } } public class MyNumbers { public int Number { get; set; } public int LastNumber { get; set; } public int TotalCount { get; set; } } }

Input:

Output:

Create and display Datatable in c# with dynamic rows and columns count

• Asp.net Code

        <div>
              <asp:GridView ID="gv" runat="server"></asp:GridView>
            <br />
            COL:
            <asp:Label ID="lblCol" runat="server"></asp:Label><br />
            ROW:
            <asp:Label ID="lblRow" runat="server"></asp:Label><br />
            <asp:GridView ID="gv1" runat="server"></asp:GridView>
            <br />
            <div id="divTitle" runat="server"></div>
        </div>

• C# Code

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

using System.Text;

namespace DynamicTable

{

    public partial class WebForm1 : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {

            DataTable table = new DataTable();

            table.Columns.Add("Job", typeof(string));

            table.Columns.Add("Col", typeof(int));

            table.Columns.Add("Row", typeof(int));

            table.Rows.Add("Data 1", 1, 1);

            table.Rows.Add("Data 2", 2, 1);

            table.Rows.Add("Data 3", 3, 1);

            table.Rows.Add("Data 4", 4, 1);

            table.Rows.Add("Data 5", 5, 1);

            table.Rows.Add("Data 6", 6, 1);

            table.Rows.Add("Data 7", 7, 1);

            table.Rows.Add("Data 8", 8, 1);

            table.Rows.Add("Data 9", 1, 2);

            table.Rows.Add("Data 10", 2, 2);

            table.Rows.Add("Data 11", 3, 2);

            table.Rows.Add("Data 12", 4, 2);

            table.Rows.Add("Data 13", 5, 2);

            table.Rows.Add("Data 14", 6, 2);

            table.Rows.Add("Data 15", 7, 2);

            table.Rows.Add("Data 16", 8, 2);

            table.Rows.Add("Data 17", 1, 3);

            table.Rows.Add("Data 18", 1, 4);

            table.Rows.Add("Data 19", 8, 3);

            table.Rows.Add("Data 20", 8, 4);

            table.Rows.Add("Data 21", 8, 5);

            table.Rows.Add("Data 22", 8, 6);

            table.Rows.Add("Data 23", 8, 7);

            table.Rows.Add("Data 24", 8, 8);

            table.Rows.Add("Data 25", 8, 9);

            gv.DataSource = table;

            gv.DataBind();

            int col = Convert.ToInt32(table.AsEnumerable().Max(row1 => row1["Col"]));

            int row = Convert.ToInt32(table.AsEnumerable().Max(row1 => row1["Row"]));

            lblCol.Text = col.ToString();

            lblRow.Text = row.ToString();

            DataTable dt = new DataTable();

            for (int i = 1; i <= col; i++)

            {

                dt.Columns.Add(i.ToString(), typeof(string));

            }

            for (int i = 1; i <= row; i++)

            {

                DataRow workRow;

                workRow = dt.NewRow();

                for (int j = 0; j < col; j++)

                {

                    DataRow drow = table.AsEnumerable().Where(p => p.Field<Int32>("Col") == j + 1 && p.Field<Int32>("Row") == i).FirstOrDefault();

                    if (drow == null)

                    {

                        // workRow[j] = "(" + i.ToString() + "," + (j + 1).ToString() + ")";

                        workRow[j] = "No_Data";

                    }

                    else

                    {

                        workRow[j] = drow["Job"].ToString();

                    }

                }

                dt.Rows.Add(workRow);

            }

            gv1.DataSource = dt;

            gv1.DataBind();

            divTitle.InnerHtml = ExportDatatableToHtml(dt);

        }

        protected string ExportDatatableToHtml(DataTable dt)

        {

            StringBuilder strHTMLBuilder = new StringBuilder();

            strHTMLBuilder.Append("<table>");

            strHTMLBuilder.Append("<tr >");

            foreach (DataColumn myColumn in dt.Columns)

            {

                strHTMLBuilder.Append("<td><div style='background-color:red;'>");

                strHTMLBuilder.Append(myColumn.ColumnName);

                strHTMLBuilder.Append("</div></td>");

            }

            strHTMLBuilder.Append("</tr>");

            foreach (DataRow myRow in dt.Rows)

            {

                strHTMLBuilder.Append("<tr >");

                foreach (DataColumn myColumn in dt.Columns)

                {

                    strHTMLBuilder.Append("<td >");

                    if (myRow[myColumn.ColumnName].ToString() != "No_Data")

                    {

                        strHTMLBuilder.Append("<div style='background-color:green;'>");

                        strHTMLBuilder.Append(myRow[myColumn.ColumnName].ToString());

                        strHTMLBuilder.Append("</div>");

                    }

                    strHTMLBuilder.Append("</td>");

                }

                strHTMLBuilder.Append("</tr>");

            }

            //Close tags.  

            strHTMLBuilder.Append("</table>");

            string Htmltext = strHTMLBuilder.ToString();

            return Htmltext;

        }

    }

}

Output:

How to validate double value in c#.net

 Add namespace: using System.Text.RegularExpressions;



if (Regex.IsMatch(txt_number.Text, @"\d+(\.\d{1,2})?"))
{
    //valid Number
    // Do something with value
}
else
{
    //invalid Number
    lbl_error.Text = "Please enter a valid number";
    return;
}

Int value validation in c#.net

            int parsedValue;
            if (int.TryParse(txt_number.Text, out parsedValue))
            {

                //valid Number
                // Do something with value
            }
            else
            {
                //invalid Number
                lbl_error.Text = "Please enter a valid number";
                return;
            }

Decimal number validation in c#.net

           decimal d;
            if (decimal.TryParse(txt_number.Text, out d))
            {
                //valid Number
                // Do something with value
            }
            else
            {
                //invalid Number
                                lbl_error.Text = "Please enter a valid number";
                return;
            }

how to set file upload size in web.config

<configuration>
  <system.web>
    <httpRuntime maxRequestLength="1024" />
  </system.web>
</configuration>

How to set first row color to gridview in c#

protected void gv1_RowDataBound(object sender, GridViewRowEventArgs e)

  {

      try

       {

                if (e.Row.RowIndex == 0)

                {

                    e.Row.BackColor = System.Drawing.Color.YellowGreen;

                }

       }

       catch (Exception ex)

       {

          lbl_error.Visible = true;

          lbl_error.ForeColor = System.Drawing.Color.Red;

          lbl_error.Text = ex.Message;

              

       }

  }

How to check if a value exists in a datatable in c#

bool exists = dt.Select().ToList().Exists(row => row["row_name"].ToString() == "value");

Difference between a Class and an object ?

Class: 

1)It is a datatype that contains the programming logic. 
2)Class is visible in the source code and resides in hard disk. 
3)Class is like a template or blueprint of the object. It implements reusability, 
encapsulation, inheritance 
example:Button is a class with properties like Text,BackColor, 
events like click, methods like Focus 

Object: 
1)it is a chunk of memory that implements the class logic. 
2)Object is in the RAM and not visible in source code. 
3)It is the real world implementation of the class. 
Each object has its own copy of data. 
example: Button1, Button2 are the objects of Button class.

Difference between Value Type and Reference Type ?

Value type	Reference type
Value type they are stored on stack	Reference type they are stored on heap
When passed as value type new copy is created and passed so changes to variable does not get reflected back	When passed as Reference type then reference of that variable is passed so changes to variable does get reflected back
Value type store real data	Reference type store reference to the data.
Value types are faster in access	Reference types are slower in access.
Value types derive fromSystem.ValueType	Reference types derive fromSystem.Object
Value type consists of primitive data types, structures, enumerations.	Reference type consists of class, array, interface, delegates
Value types can not contain the valuenull.	Reference types can contain the valuenull.