Extension methods in C#

Extension methods in C#

public static void AllowWholeNumberOnly(this KeyPressEventArgs e)
{
if (!char.IsDigit(e.KeyChar)) e.Handled = true;
if (e.KeyChar == (char)8) e.Handled = false;
}

public static void AllowNumbericValueOnly(this KeyPressEventArgs e)
{
if (!char.IsDigit(e.KeyChar)) e.Handled = true;
if (e.KeyChar == (char)8) e.Handled = false;
if (e.KeyChar == (char)46) e.Handled = false;
}

public static bool AllowDecimalValueOnly(object sender, KeyPressEventArgs e)
{
var IsValid = false;
IsValid = (((e.KeyChar < 48 || e.KeyChar > 57) && e.KeyChar != 8 && e.KeyChar != 46)) ? true : false;

// checks to make sure only 1 decimal is allowed
if (e.KeyChar == 46)
{
IsValid = ((sender as TextBox).Text.IndexOf(e.KeyChar) != -1) ? true : false;
}

return IsValid;
}

public static void AllowAlphabeticalValueOnly(this KeyPressEventArgs e)
{
if (char.IsDigit(e.KeyChar)) e.Handled = true;
if (e.KeyChar == (char)8) e.Handled = false;
if (e.KeyChar == (char)46) e.Handled = false;
}

Reverse the string

Reverse the string

Reverse the string by for Loop


using System;

namespace ConsoleApp
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            string inputString = Console.ReadLine();
            string reverse = ReverseString(inputString);
            Console.WriteLine(string.Format("Reverse string of {0} is {1}", inputString, reverse));
            Console.ReadLine();
        }

        public static string ReverseString(string inputString)
        {
           string reveseString = "";
            char[] inputStringArr = inputString.ToCharArray();
            for (int i = inputStringArr.Length - 1; i <= inputStringArr.Length && i >= 0; i--)
            {
                reveseString += inputStringArr[i];
            }
            return reveseString;
        }
    }
}

Reverse the string by While Loop

using System;

namespace ConsoleApp
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            string inputString = Console.ReadLine();
            string reverse = ReverseString(inputString);
            Console.WriteLine(string.Format("Reverse string of {0} is {1}", inputString, reverse));
            Console.ReadLine();
        }

        public static string ReverseString(string inputString)
        {
            string reveseString = "";
            char[] inputStringArr = inputString.ToCharArray();
            int j = inputStringArr.Length - 1;
            while (j >= 0)
            {
                reveseString += inputStringArr[j];
                j--;
            }
            return reveseString;
        }
    }

}

Minimum in SubArrays

Minimum in Sub Arrays


You are given an array A[] of size N and an integer K.
Your task is to print the Minimum element for each subarray of size 'k'.
In other words, for Each Valid Index i (1 <= i <= N - K)
You have to print min(A[i], A[i + 1], A[i + 2] .... A[i + k]).

Input Format
The First line will contain two Integers N and K.
The Second Line will contain N Integers denoting the elements of Array A[].

Constraints

1 <= N <= 10^5

1 <= K <= N

1 <= A[i] <= 10^6

Output Format

Print the Minimum elements for each subarray of Size K separated by space.

Sample TestCase 1

Input

5 2

10 0 3 2 5

Output

0 0 2 2

Code:

using System;

using System.Linq;

namespace ConsoleApp

{

    internal class DonNetTest

    {

        private static void Main(string[] args)

        {

            string inputFirstLine = System.Console.ReadLine();

            string[] firstLine_arr = inputFirstLine.Split(' ').ToArray();

            int n = Int32.Parse(firstLine_arr[0]);

            int k = Int32.Parse(firstLine_arr[1]);

            int[] arr = new int[k];

            string inputSecondLine = System.Console.ReadLine();

            string[] secondLine_arr = inputSecondLine.Split(' ').ToArray();

            arr = Array.ConvertAll(secondLine_arr, Int32.Parse);

            printMinimumArray(n, k, arr);

        }

        private static void printMinimumArray(int n, int k, int[] arr)

        {

            int j, min;

            for (int i = 0; i <= n - k; i++)

            {

                min = arr[i];

                for (j = 1; j < k; j++)

                {

                    if (arr[i + j] < min )

                        min = arr[i + j];

                }

                Console.Write(min + " ");

            }

        }

    }

}

Simple and Trick Question Answer SQL

Q.1 Below query will execute or give error.
     
       SELECT *,YEAR(CreatedOn) AS Yr FROM Customer WHERE YEAR(CreatedOn) > 2017;


Ans :-It will give records which year is greater than 2017.


Q.2 Below query will execute or give error.
 
SELECT CASE WHEN NULL=NULL THEN 'YES' ELSE 'NO' END

Ans :- Execute - NO

Q.3 What will be result?

    a)   SELECT COUNT(*);
    b)   SELECT SUM(NULL);

ANS :-  a) 1
             b) Operand data type NULL is invalid for sum operator.              

Q.4 Single query for update swap record?

       e.g  :- if customer table have one column i.e. Gender and some are Female & some Male then                update Female to Male & Male to Female.

ANS :-

     UPDATE Customer
     SET Gender = (CASE WHEN Gender='Female' THEN 'Male' ELSE 'Female' END);

Q.5 How to get nth salary in sql?

ANS :-
             WITH ResultCTE AS
              (
                 SELECT Salary,DENSE_RANK() OVER (ORDER BY Salary DESC) as DeskRank
                 FROM Employee
               )
              SELECT Salary FROM ResultCTE  WHERE ResultCTE .DeskRank=nth;

Q.6 How to delete duplicate record from table?

ANS :-
             WITH ResultCTE AS
              (
                 SELECT *,Row_Number() OVER (Partition by Id ORDER BY Id) as RowNumber
                 FROM Employee
               ) 
              DELETE From ResultCTE WHERE RowNumber > 1;

Access-Control-Allow-Origin Header in ASP.NET Core Web API

Add Setting in Startup Class.


 public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();
            services.AddCors();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            app.UseCors(builder =>
            {
                builder.AllowAnyHeader()
                       .AllowAnyOrigin()
                       .AllowAnyMethod();
            });
            app.UseMvc();
        }
    }

allow only numbers or decimal in textbox

Allow only numbers or decimal in textbox

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="RNDWithNumbers.aspx.cs"

    Inherits="TabFormWebApp.RNDWithNumbers" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title></title>

    <script src="Script/jquery.min.js" type="text/javascript"></script>

    <script type="text/javascript">

        function isNumberWithDecimalKey(evt, obj) {

            var charCode = (evt.which) ? evt.which : event.keyCode

            var value = obj.value;

            var dotcontains = value.indexOf(".") != -1;

            if (dotcontains)

                if (charCode == 46) return false;

            if (charCode == 46) return true;

            if (charCode > 31 && (charCode < 48 || charCode > 57))

                return false;

            return true;

        }

        function isNumber(evt) {

            evt = (evt) ? evt : window.event;

            var charCode = (evt.which) ? evt.which : evt.keyCode;

            if (charCode > 31 && (charCode < 48 || charCode > 57)) {

                return false;

            }

            return true;

        }

    </script>

</head>

<body>

    <form id="frm" runat="server">

    <table>

        <tr>

            <td>

                Only Number

            </td>

            <td>

                <input type="text" id="txtAllowNumber" onkeypress="return isNumber(event)" />

            </td>

        </tr>

        <tr>

            <td>

                Only Number With Decimal

            </td>

            <td>

                <input type="text" id="txtAllowNumberWithDecimal" onkeypress="return isNumberWithDecimalKey(event,this)" />

            </td>

        </tr>

    </table>

    <br />

    </form>

</body>

</html>

MongoDB CRUD Operations

MongoDB CRUD Operations

 CREATE DATABASE IN mongoDB

  MongoDB use DATABASE_NAME is used to create database. The command will create a new database if it doesn't exist, otherwise it will return the existing database.

Syntax

syntax of create database is as follows - e.g. : use DataBaseName

Like :- use TestDB

Note :- CURD means  create, read, update, and delete

1 :- CREATE COLLECTION

MongoDB createCollection(name, options) is used to create collection.

e.g :- db.createCollection("Student", { size: 2147483648 } )

2 :- CREATE OPERATIONS

                       

syntax :- 1) db.collection.insertOne()

              2) db.collection.insertMany()  

Note:- (INSERT Data into Collection)

e.g :-1--) if insert one record

 db.Student.insertOne( { name: "mohan", class: "BCA", rollno :5} );

e.g :- 2--) if insert multiple record at one time

db.Student.insertMany( [

        { name: "mohan", class: "BCA", rollno :5},

        { name: "sohan", class: "MBA", rollno :15},

        { name: "ram", class: "BBA", rollno :10},

        { name: "shyam", class: "MCA", rollno :25},

   ] );

3 :- READ OPERATIONS

syntax : db.collection.find(query, projection)

e.g :- db.Student.find()

e.g :-1) db.Student.find({ name: "shyam" })

e.g :-2) db.Student.find( { rollno : 5 } )

4 :- UPDATE OPERATIONS

syntax :- db.collection.update(selectQuery, udateQuery)

e.g :-1 ) 

db.Student.update({'name':'shyam'},{$set:{'name':'shyam kumar'}})

db.Student.update({'id':'2'},{$set:{'name':'Mohan kumar'}})

e.g :-2) 

Note:- update class where rollno is greater than 10

db.Student.updateMany(

      { rollno : { $gt: 10 } },

      { $set: { "class" : 'PHD'} }

   );

5 :- DELETE OPERATIONS

syntax :-1 ) db.collection.deleteOne()

           :-2 ) db.collection.deleteMany()

e.g:- 1)

db.Student.deleteOne( { rollno : 4 } )