PUSH and POP algorithms in Linked List implemented STACK in C Language

To implement the STACK using Linked List, the following PUSH and POP algorithms may be used:

Algorithm for PUSH operation in Linked List implemented STACK:

PUSHLL(TOP, ITEM)
[TOP is address of top node of STACK and ITEM is the item to PUSH.[In case of Linked List no overflow, but may be memory allocation error]
If AVAIL=NULL then:
  Write: ’Memory Allocation Error !!!’; Exit.
[End of If]
NEW<--AVAIL
AVAIL<--AVAIL-->LINK
NEW-->INFO<--ITEM
NEW-->LINK<--NULL
If TOP=NULL Then:
  TOP<--NEW
Else:
  NEW-->LINK<--TOP
   TOP<--NEW
[End of If]
Exit.

For Linked List implemented STACK in C, a self-referential structure, a user defined data type STACK is used, it is as follows:
struct STACK
  {
    int i:
    STACK *link:
   };

Algorithm for POP operation in Linked List implemented STACK.
POPLL(TOP)
[TOP is the address of TOP node of STACK]
If TOP=NULL Then:
   Write: ‘Underflow’
   Exit.
[End of If]
ITEM <--TOP-->INFO
TOP<--TOP-->LINK
Return ITEM
Exit.

QUEUE in C Language

• It’s special data structure based on FIFO (First In First out Concept).
• It can be implemented using One dimensional Array as well as Singly linked list.
• REAR and FRONT are the two external pointers holds the addresses of two ends respectively.
• Insertion and deletion are done from two different ends known as REAR and FRONT respectively.  

 Types of Queue:

• Linear Queue: Elements are arranged in a linear order.
• Circular Queue: Elements are arranged in a queue by means of circular array.
• D-Queue.( Double Ended QUEUE ) The ADD and DELETE operations are done from both the ends.
• Priority QUEUE: The elements are stored and deleted in QUEUE on this basis of Priority.

Linear Queue:

Algorithm using Linked List:

CREATELQ( ARR, N , FRONT , REAR, ITEM)

[ ARR is the name of the array of size N. ITEM is the info. of element inserted in queue]

If REAR = N Then:

Write: ‘ Overflow’

Exit

[ End of If ]

If REAR = 0 Then:

FRONT <-- 1

REAR <-- 1

Else: 

REAR <-- REAR + 1

[ End of If]

ARR[REAR] <--  ITEM

Exit

Algorithm for DELETE operation in Linear Queue:

DELETELQ ( ARR, FRONT, REAR)

[ ARR is name of the array of size N]

If   FRONT=NULL Then:

    Write: ‘ Empty Queue’

    Exit

[ End of If ]

ITEM <-- FRONT --> INFO

If REAR = FRONT Then:

    REAR <-- NULL

    FRONT <-- NULL

Else

    FRONT <-- FRONT --> NEXT

[ End of If]

Write: ‘Deleted Element ‘, ITEM

END

Algorithm using  One dimensional Array.

ADDLQ(QUEUE,N, ITEM, REAR, FRONT)

If REAR=N Then:

   Write: ‘ OverFlow’

   Exit

[ End of If]

If REAR = -1 Then:

   REAR <-- 0

   FRONT <-- 0

Else

   REAR <-- REAR +1

[ End of If]

QUEUE[ REAR] <-- ITEM

END

DELETELQ(QUEUE , REAR, FRONT)

If FRONT =-1 Then:

    Write: ‘ Empty Queue’

    Exit

[ End of If ]

Write: ‘ Deleted Element’ FRONT --> INFO

If FRONT= REAR Then:

    FRONT= -1

    REAR= -1

Else

   FRONT <-- FRONT --> NEXT

[ End of If]

End

Circular Queue:

ADDCQ(QUEUE,N, ITEM, REAR, FRONT)

If FRONT =REAR +1REAR=N Then:

   Write: ‘ OverFlow’

   Exit

[ End of If]

If REAR = -1 Then:

   REAR <-- 0

   FRONT <-- 0

Else

   REAR <-- REAR +1

[ End of If]

QUEUE[ REAR] <-- ITEM

END

Validate TextBox inside Footer Row of Gridview in ASP.NET

Introduction

Validation of TextBox is already performed earlier. Now, in this post i will do apply the same validation on the TextBox control. But, at this time TextBox inside in GridView control. So, For this type of problem, i have two solution. Before performed all actions, we should bind the gridview with datasource. Now, we can apply validation on the TextBox, which is inside in FooterRow of GridView.  I have a database table, which is used mentioned example:

I-Method (Using RequiredFieldValidator)

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" ShowFooter="true">

            <Columns>
                <asp:TemplateField HeaderText="Program Id">
                    <ItemTemplate>
                        <asp:Label ID="progid" runat="server" Text='<%# Eval("prog_id") %>' />
                    </ItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="fid" runat="server"></asp:TextBox>

<asp:RequiredFieldValidator ControlToValidate="fid" ForeColor="red" ID="RequiredFieldValidator1" runat="server" ErrorMessage="*"></asp:RequiredFieldValidator>
                     
                    </FooterTemplate>

                </asp:TemplateField>

            </Columns>

        </asp:GridView>
By this method we have to attach RequiredField Validator control with the TextBox control.

II-Method(Using JavaScript)

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script type="text/javascript">
        function valiadte() {
            var ftid = document.getElementById('<%=((TextBox)GridView1.FooterRow.FindControl("fid")).ClientID %>');
            if (ftid.value != '') {
                alert("Sucess");

            }
            else {
                alert("field is required");
            }

        }

    </script>
 
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" ShowFooter="true">
            <Columns>
                <asp:TemplateField HeaderText="Program Id">
                    <ItemTemplate>
                        <asp:Label ID="progid" runat="server" Text='<%# Eval("prog_id") %>' />
                    </ItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="fid" runat="server"></asp:TextBox>

             
                    </FooterTemplate>
          </asp:TemplateField>
          </Columns>
 </asp:GridView>
    </div>
     
        <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="valiadte();" />
       </form>
</body>
</html>

Code generate the following out-- see the video 

Download : Full code of program
In the second method, first we access the id of the TextBox with the help of java script function, which is mentioned in the program after that check the value of the Control , if TextBox is empty then generate the alert message on the screen.

Generate QRCODE in ASP.NET

Introduction QRCode

Data display in the form of matrix, Actually i am saying to you that you data hide behind the image. First time this code is designed in japan. If you want to read more about QRCode click it.  Here i have a library to generate QRCode image for your data.

Generate code from nuget.org library

First to download MessagingToolkit.QRCode.dll assembly from Nuget source using some steps:
1. Tools--Nuget Package Manager--Manage Nuget Packages for solution.
2. Search QRcode as text in Search bar. Now, appear some library in the middle pane.

3. Add a web form in solution. Now, I have two page one page is source page(Default2.aspx) and other one is code behind page(Default2.aspx.cs).
4. Add a Image control from the toolBox in design window of Default2.aspx page. Now, the source page look like

 <asp:Image ID="img" runat="server"/>

5. Now, add this code in code behind file.

using System.Drawing;
using System.Drawing.Imaging;
using MessagingToolkit.QRCode.Codec.Data;
using MessagingToolkit.QRCode.Codec;

protected void Page_Load(object sender, EventArgs e)
    {
     
        QRCodeEncoder encoder = new QRCodeEncoder();
        Bitmap hi = encoder.Encode("http://dotprogramming.blogspot.com");
        hi.Save(Server.MapPath("~/imageFolder/ji.jpg"),ImageFormat.Jpeg);
        img.ImageUrl = "~/imageFolder/ji.jpg";



    }

Here, imageFolder is a directory which is exist in the project solution.

Code Generate the following output

Download Full Source code

II-Method

To generate QR Code image. First to Download QRcode library from the codeplex site.

Webform Source page:
<form id="form1" runat="server">
    <div>
    <asp:Image ID="img" runat="server" Height="142px" Width="124px" />
    </div>
    </form>

CodeBehind file

protected void Page_Load(object sender, EventArgs e)
    {

        QrEncoder encode = new QrEncoder();
        QrCode code = encode.Encode("hello world");
        Bitmap hi = new Bitmap(code.Matrix.Width, code.Matrix.Height);
        for (int i = 0; i<=code.Matrix.Width-1; i++)
        {
            for (int j = 0; j < code.Matrix.Height-1; j++)
{
if(code.Matrix.InternalArray[i,j])
             {
                 hi.SetPixel(i, j, System.Drawing.Color.LightBlue);

             }
             else
             {
                 hi.SetPixel(i, j, System.Drawing.Color.DarkBlue);
             }
}
        }
        hi.Save(Server.MapPath("~/imjk/ji.jpg"),ImageFormat.Jpeg);
        img.ImageUrl = "~/imjk/ji.jpg";



    }

How to add Text with value in Dropdownlist in ASP.NET code file

Introduction

Dropdownlist is a string collection control class. Through the ListItem class, we can add some string into it. If we add some item into it in the code file only one string can add in it. Like

Dropdownlist1.items.add(String item);

But at the compile/Design time, we can add text as well as value in it. At the compile time, visual Studio IDE use ListItem class for data insertion. ListItem class provide overloaded constructor, Through this we can add both Text and Value.

Example:
Source code of the file : Complete Code Download

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default5.aspx.cs" Inherits="Default5" %>

<!DOCTYPE html>

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

<head runat="server">

    <title></title>

   

</head>

<body>

    <form id="form1" runat="server">

        <asp:DropDownList ID="DropDownList1" runat="server"></asp:DropDownList>

        <p>

        <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />

      

        </p>

        <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>

      

    </form>

</body>

</html>

Code Behind file

using System;

using System.Collections.Generic;

using System.Configuration;

using System.Data.SqlClient;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

public partial class Default5 : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

    if(!Page.IsPostBack)

    {

        DropDownList1.Items.Add(new ListItem("Apple", "20"));

        DropDownList1.Items.Add(new ListItem("Mango", "30"));

        DropDownList1.Items.Add(new ListItem("Grapes", "40"));

    }

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        Label1.Text = DropDownList1.SelectedValue;

    }

}

Code Generate the following output

In this example, we have three control on design. First to add Text with value in the DropdownList using the ListItem class. Now, On button click, we accessed the selected item value of control in the label.

Polish Notation for Data Structure in C Language

Polish Notation

Normally in an arithmetic expression the operator is placed in between the operands or expression. Such an expression is called as INFIX expression. In an INFIX expression according to the need the parentheses are placed according to the need. The parentheses are placed to find the value overhauling the operator hierarchy. Considering the operator hierarchy it is not possible to find the value of INFIX expression in one scan. Several scans are needed if an INFIX expression contains different hierarchy operators.

Following is a simple list of binary operators with hierarchy. Binary operators are those which involve two operands or expressions to frame an expression.

Level 1     ! Exponent (to find power, A ! B, A to the power B)

Level 2   */ Multiplication, Division, same hierarchy

Level 3    +-Addition, Subtraction, same hierarchy

In an INFIX expression, if the different operators are used to frame the expression ,then the expressions involving highest hierarchy are evaluated first scanning from left to right. The resulting expression is again evaluated for the next expression or value. If any parentheses are there they are removed by finding the value within the parentheses. So an expression is evaluated after multiple passes.

For example consider an expression:

                                          6 * 3 ! 2 / (3+6)

After first pass                   6 * 3 !  2 / 9

After second pass              6 * 9 / 9

After third pass                             6        Final value

       In computer it consumes much time. In order to overcome these difficulties French mathematician Polish has given different ways of writing an INFIX expression. He has given parentheses free notation called Polish notation in which the operator is placed before the operands, such notation is called as ‘Polish Notation’. As the operators are placed before the operands the resulting expression is called as PREFIX expression.

                     If the operators are placed after the operands the resulting notation is called as RPN, Reverse Polish Notation and the resulting expression is called as POSTFIX expression.

INFIX        - Operators in between operands / sub expressions

PREFIX     -Operators before operands / sub expressions

POSTFIX   -Operators after operands / sub expression

Conversion of an INFIX expression to POSTFIX expression using STACK in C language

Conversion of an INFIX expression to POSTFIX expression using STACK
                          STACK finds an application in converting an INFIX expression to POSTFIX expression. In this application STACK is used store the operators as items.

Procedure:

In order to convert an INFIX expression to POSTFIX expression. Call an INFIX expression as I and a POSTFIX expression as P. Add a’)’,right parentheses, at the end of I and PUSH a’ (‘,left parentheses on to STACK.. Scan I, from left to right till STACK is empty.
  If the second character is operands like 2, 3, 4 or a, b, c etc just add it to P.If the scanned character is’(‘,a left parentheses then PUSH it on to the STACK.The resulting expression P is the POSTFIX expression.

For example, consider an INFIX expression: 8*3/2 ! (2+1)

First add a ‘)’ at the end of INFIX expression and call it I.

Scan I till STACK is empty. Scanned character for the first time is 8, an operand add it to P.
P:8
Next scanned character is *, an operator PUSH it on to the STACK.

Next scanned character is 3, an op[errand add it to P.

P:8  3

Next scanned character is /, an operator, check the TOP of STACK, it contains*, * is having same hierarchy as/, so POP it and add it to P. After that the TOP of STACK is ‘(‘,so PUSH scanned character  /, on to STACK.

P:8    3 *