Other Remaining Operators used in JAVA Programming

All other remaining operators except assignment operators are listed in this article. Like instance of, shift operators, bitwise and many more described with example in the article.

The following table lists the other operators that the Java programming language supports.

In the following lines, we are discussing some of these operators. Discussion of all these operators may be large task here.

Conditional operator ?:

Java offers a shortcut conditional operator (?:) that store a value depending upon a condition. This operator is ternary operator i.e., it requires three operands. The general form of conditional operator ?: is as follows:
expressiona1 ? expression2 : expression3

If expression1 evaluates to true i.e., 1, then the value of the whole expression is the value of expression2, otherwise, the value of whole expression is the value of expression3. For instance
result = marks >= 50  ?  ‘P’ : ‘F’ ;

The identifier result will have value ‘P’ if the test expression marks >= 50 evaluates to true otherwise result eill have value ‘F’. Following are some more examples of conditional operator ? :

6 > 4 ? 9 : 7 evaluates to 9 because test expression 6 > 4 is true.
4 == 9 ? 10 : 25 evaluates to 25 because test expression 4 == 9 is false.

The conditional operator might be fascinating you but certainly one tip regarding ? :, we would like all of you to keep in mind and which is being told in form of following tip.
Beware that the conditional operator has a low precedence.The conditional operator has a lower precedence than most other operators that may produce unexpected results sometimes. Consider the following code:
n = 500;
bonus = n + sales > 15000 ? 250 : 50 ;

The above code is trying to add n and the value 250 or 50 depending upon whether sales > 15000 is true or false. But this code will not work in the desired manner. The above code will be interpreted as follows:
bonus = (n + sales) > 15000 ? 250 : 50;

Because operator ‘+’ has higher precedence over > and ?:
Therefore, for the desired behaviour the conditional expression should be enclosed in parentheses as shown below:
bonus = n + (sales > 15000 ? 250 : 50) ;

The [ ] Operator

The square brackets are used to declare arrays, to create arrays, and to access a particular element in an array. Similar data items, such as marks of 20 student or sales of 30 salesmen etc., are combined together in the form of arrays. Here’s an example of an array declaration
Float [ ] arrayofFloats = new float[10] ;

The previous code declares an array that can hold ten floating point numbers. Here’s how you would access the 7th item in that array :
arrayOfFlooats[6];

Please note that first element of array is referred to as array-named[0] i.e., to refer to first item of array namely arrayOfFloats, we shall write arrayOfFloats[0]. We are not going into further details of arrays right now.

The . Operator

The dot (.) operator accesses instance members of an object or class members of a class.

The ( ) Operator

When declaring or calling a method, the method’s arguments are listed between parenthesis ( and ). You can specify an empty argument list by using ( ) with nothing between them.

The ( type ) Operator

This operator casts ( or “ convent “ ) a value to the specified type. You’ll see the usage of this operator a title later in this chapter, under the topic Type Conversion.

The new Operator

You can use the new operator to create a new object or a new array. You’ll find examples highlighting the usage of new operator in a later section – Objects as instances of class – in this chapter.

The instance of Operator

The instanceof operator tests whether its first operand is an instance of second.
Op1  instanceof   op2

Op1 must be the name-of-an-object and op2 must be the name -of -a –class. An object is considered to be an instance of a class if that object directly or indirectly descends from that class.

Assignment Operators

Assignment and Shorthand Assignment Operators used in JAVA with Example

Java provides some assignment and shorthand operators listed in the article with example of each. The article also explains a table with all these assignment operators provided by JAVA Programming.

Like other programming languages, Java offers an assignment operator =, to assign one value to another e.g.
int x, y, z;
x = 9;
y = 7;
z = x + y;
z = z * 2;

Java shorthand Operators

Java offers special shorthand operators that simplify the coding of a certain type of assignment statement. For example,
a = a + 10; may be written as a += 10;

The operator pair += tells the compiler to assign to a value of a + 10. This shorthand works for all the binary operators in Java (those that require two operands). The general form of Java shorthand is
var = var operator expression same as var operator = expression

Following are some examples of Java shorthands:
X   -= 10; equivalent to x = x-10;
X*=3; equivalent to x=x*3;
X /=2; equivalent to x=x/2;
X%=z; equivalent to x=x%z;

Thus, we can say (=,*=, /=, %=, -=) are assignment operators in Java. The operators (*=, /=, %=, += and -=) are called arithmetic assignment operators. One important and useful thing about such arithmetic assignment operators of Java is that they combine an arithmetic operator and an assignment operator, and eliminate the repeated operand thereby facilitate a condensed approach.

The following table lists some shortcut assignment operators and their lengthy equivalents:

How to find last day of month in ASP.NET C#

Introduction

If you want to get last day of this month , use DateTime structure with AddMonths( ) method. using this method you can get first day of next month. Now, create a new instance of DateTime structure with some parameter like DateTime(Int32, Int32, Int32). This parameterized method Initializes a new instance of the DateTime structure to the specified year, month, and day. Here you can pass integer 1 in day field. Now, you can delete 1 day from current DateTime object using AddDays (-1) method. Now, your object will return last day of current month.

<form id="form1" runat="server">
    <div>  
        <asp:Button ID="Button1"
         runat="server"
         onclick="Button1_Click"
         Text="Click"
         BackColor="#99CCFF" />  
    </div>
        <asp:Label ID="Label1"
         runat="server"
         Text="Label"
         BackColor="Yellow"></asp:Label>
    </form>
Code Behind
protected void Button1_Click(object sender, EventArgs e)
        {        
            DateTime today = DateTime.Today;          
            DateTime tempDate = today.AddMonths(1);
            DateTime tempDate3 = new DateTime(tempDate.Year, tempDate.Month, 1);
            DateTime Monthlastday = tempDate3.AddDays(-1);
            Label1.Text = "Today : " + today.ToLongDateString();
            Label1.Text += "<br /><br />month last day= ";
            Label1.Text += Monthlastday.ToLongDateString();

        }

Code generate the following output

How to put an image into a Button in WPF

Introduction

Window Presentation Foundation support Rich Composition, in which you can use a control as a container. In this example i will show, how to put an image into a Button control. If you want to make highly visualize application, must use WPF, because of the strict separation of appearance and behavior you can easily change the look of a control. Now, lets take an simple example

Source Code (xaml file)

<Grid>

    <Button>

        <StackPanel Orientation="Horizontal" Width="155">

                <Image Source="home.jpg " Height="33" Width="66" Stretch="Uniform"/>

            <TextBlock Text=" Home" FontSize="20"/> 

            

 </StackPanel>

    </Button>

    </Grid>

Code Generate the following output

According to above mentioned source code, A Button control contains a stack panel so its work as a container. We already learn about stack panel in previous article. In client based application you can design more powerful application using WPF.

How to use LINQ Aggregate operators in ASP.NET

Introduction

The Aggregate operators compute a single value from a collection. The different Aggregate operators are: Aggregate, Average, Count, LongCount, Max, Min, and Sum. The Aggregate clause calculates a sum value of the values in the collection. The Average clause calculates the average value of the collection of the values. The Count clause counts the elements in the collection. The LongCount clause counts the elements in a large collection. The Max clause determines the maximum value in a collection. The Min clause determines the minimum value of the collection. The Sum clause calculates the sum of values in the collection.
The syntax of the Count clause is:
For C#
public static int Count<T>( this IEnumerable<T> source, Function<T, bool> predicate);
The Count clause throws an ArgumentNullException exception, if any argument is null and an OverflowException exception is thrown if the count exceeds the maximum value.
The syntax of the Sum clause is:
For C#
public static Numeric Sum<T>( this IEnumerable<T> source, Function<T, Numeric> selector);

The Sum clause returns 0 for an empty sequence. The clause does not include null values in its result.
The Aggregate clause applies a function over a sequence.
The syntax of the Aggregate clause is:
For C#
public static T Aggregate<T>( this IEnumerable<T> source, Function<T, T, T> func);
The LongCount clause counts the number of elements in the given sequence.
The syntax of the LongCount clause is:
For C#
public static lonq LonqCount<T>( this IEnumerable<T> source);
The Min clause finds the minimum value of the given sequence.
The syntax of the Min clause is:
For C#
public static T Min<T>(this IEnumerable<T> source);
The Max clause returns the maximum value of the given sequence.
The syntax of the Max clause is:
For C#
public static T Max<T>(this IEnumerable<T> source);

The Average clause computes the average of the given sequence.
The syntax of the Average clause is:
For C#
public static Result Average(this IEnumerable<Numeric> source);

Lets take an simple example

<form id="form1" runat="server">
    <div>
    
        <asp:ListBox ID="ListBox1" runat="server" Height="176px" Width="267px">
        </asp:ListBox>
        <br />
        <br />
        <asp:Button ID="Button1" runat="server" onclick="Button1_Click" 
            Text="Agg. Operator Ex" Width="107px" />
    
    </div>
    </form>
Code Behind
protected void Button1_Click(object sender, EventArgs e)
    {
        int[] num = { 5, 4, 3, 2, 1, 7, 8, 9, 10, 34, 67 };
        double sum = num.Sum();
        ListBox1.Items.Add("The Sum of the Number is= " + sum);
        int minimum = num.Min();
        ListBox1.Items.Add("Minimum Number is= " + minimum);
        int oddnum = num.Count(n => n % 2 == 1);
        ListBox1.Items.Add("Count of the odd Number is= " + oddnum);

    }
Code Generate the following output

How to Create CheckboxList in Asp.Net MVC

CheckboxList is used to provide some options to be select by the user. In this article we will create a list of items and then pass it to view to create a checkbox list.

Create two classes with the following format

public class CollectionVM
{
    public List<ChoiceViewModel> ChoicesVM { get; set; }
    public List<Int64> SelectedChoices { get; set; }
}

public class ChoiceViewModel
{
    public Int64 SNo { get; set; }
    public string Text { get; set; }
}

In controller’s action method write following code in which we will create a new list having some items created below. When we return this ViewModel in the view, we first set the SelectedChoices object to a new blank list of same type.

CollectionVM collectionVM = new CollectionVM();
List<ChoiceViewModel> choiceList = new List<ChoiceViewModel>();
choiceList.Add(new ChoiceViewModel() { SNo = 1, Text = "Objective Choice 1" });
choiceList.Add(new ChoiceViewModel() { SNo = 2, Text = "Objective Choice 2" });
choiceList.Add(new ChoiceViewModel() { SNo = 3, Text = "Objective Choice 3" });
choiceList.Add(new ChoiceViewModel() { SNo = 4, Text = "Objective Choice 4" });

collectionVM.ChoicesVM = choiceList;
collectionVM.SelectedChoices = new List<long>();
return View(collectionVM);

In View page start a loop to create individual checkbox and label for each item added above.

@using (Html.BeginForm())
{
    <div>
        <ul>
            @foreach (var choice in Model.ChoicesVM)
            {
                <li>
                    <input 
                                id="choice@(choice.SNo)"
                                type="checkbox" 
                                name="SelectedChoices"
                                value="@choice.SNo"
                                @(Model.SelectedChoices.Contains(choice.SNo) ? "checked" : "")/>
                    <label for="operator@(choice.SNo)">@choice.Text</label>
                </li>
            
            }
        </ul>
        <input type="submit" value="Submit" name="submitBtn" id="submitBtn" />
    </div>
}

Check out above very simple code through which we will set all the checked item's sNo in the object SelectedChoices we have sent by viewmodel. And in the second line, particular label have been designed for each checkbox.

Now what happen when we submit this form. Write the HttpPost method of same action having this Viewmodel as parameter like:

[HttpPost]
        public ActionResult Index(CollectionVM collectionVM)
        {

This collectionVM object have all the SNo's of checked items by user. So we have created a checkbox list and then access all the checked items in our controller's action.

Use Multiple models in single view

How to Use Multiple Models in View using ViewModel: Asp.Net MVC

Asp.Net MVC uses such type of classes in which each field may contains specific validation rules using data annotations, to let the user interact with those only. These fields may contains some extra fields to be used as a temporary purpose.

Create two classes in the Models folder named Student and Employee as written below:

public class Student
{
public string Name { get; set; }
public int Age { get; set; }
public string City { get; set; }
}
public class Employee
{
public int EmpId { get; set; }
public string EmpName { get; set; }
}

Create a folder in our solution named ViewModels and add a class named Student_EmployeeViewModel which will have the following code.

public class Student_EmployeeViewModel
{
public List<Student> Students { get; set; }
public List<Employee> Employees { get; set; }
}

Come to our Controller (Home controller) and add an Action (Student_Employee) which will be type of HttpGet. This action will have some lines of code as below which contains two list of student and employee and then assign them to the newly created object of Student_EmployeeViewModel.

public ActionResult Student_Employee()
{
List<Student> studentList = new List<Student>();
studentList.Add(new Student() { Name = "Student 1", Age = 24 });
studentList.Add(new Student() { Name = "Student 2", Age = 25 });
studentList.Add(new Student() { Name = "Student 3", Age = 23 });

List<Employee> empList = new List<Employee>();
empList.Add(new Employee() { EmpName = "Employee 1", EmpId = 101 });
empList.Add(new Employee() { EmpName = "Employee 2", EmpId = 102 });
empList.Add(new Employee() { EmpName = "Employee 3", EmpId = 103 });

Student_EmployeeViewModel vm = new Student_EmployeeViewModel();
vm.Students = studentList;
vm.Employees = empList;
return View(vm);
}

Create an empty view by right clicking on this action and then Add View dialog box as discussed earlier. Write the following code in this view which will have two list as defined in our ViewModel.

@model MvcApplication1.Models.Student_EmployeeViewModel

@{
    ViewBag.Title = "Student_Employee";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Students List</h2>

@foreach (var item in Model.Students)
{
    <option>@item.Name &nbsp;&nbsp; @item.Age</option>
}

<h2>Employees List</h2>

@foreach (var item in Model.Employees)
{
    <option>@item.EmpName &nbsp;&nbsp; @item.EmpId</option>
}

In the above code, we run two loops for each list of student and employee and display their name and age/id on the page.

Run this project and write the address of this action in the address bar, this will shows all the data of student as well as employees we have added in the action.

Create DropDownList in MVC
Create CheckboxList in MVC