print barcode with vb.net 12: Operator Overloading in C#.NET

Making USS Code 128 in C#.NET 12: Operator Overloading

12: Operator Overloading
Generating USS Code 128 In Visual C#
Using Barcode creation for VS .NET Control to generate, create ANSI/AIM Code 128 image in Visual Studio .NET applications.
www.OnBarcode.com
USS Code 128 Decoder In Visual C#
Using Barcode reader for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
return false; }
Generate UPC Code In Visual C#.NET
Using Barcode creator for .NET Control to generate, create UCC - 12 image in .NET framework applications.
www.OnBarcode.com
ANSI/AIM Code 39 Drawer In Visual C#.NET
Using Barcode creation for .NET Control to generate, create Code 39 Extended image in .NET applications.
www.OnBarcode.com
Notice that there s no else clause here. If the numerator and denominator are equal, the operator returns true, and exits. If they re not equal, the return statement after the if is executed, so there s no need for an else. C# insists that if you overload the equals operator, you must also overload the notequals operator (!=). It s good programming practice to have the inequality operator delegate its work to the equality operator, like this:
Quick Response Code Creation In C#.NET
Using Barcode generator for .NET Control to generate, create QR Code image in .NET applications.
www.OnBarcode.com
Matrix 2D Barcode Creator In C#.NET
Using Barcode encoder for .NET framework Control to generate, create Matrix image in .NET applications.
www.OnBarcode.com
public static bool operator !=(Fraction lhs, Fraction rhs) { return !(lhs==rhs); }
Linear Creation In Visual C#
Using Barcode drawer for .NET framework Control to generate, create Linear 1D Barcode image in .NET framework applications.
www.OnBarcode.com
Draw RM4SCC In Visual C#
Using Barcode drawer for VS .NET Control to generate, create British Royal Mail 4-State Customer Code image in .NET framework applications.
www.OnBarcode.com
As you can see, the != operator will return the opposite of the value of the == operator, which is exactly what you want. This way, if you change your definition of equality, you can change the code in the == operator overload, and the != operator will still return the opposite. Similarly, the less than (<) and greater than (>) operators must be paired, as must the less than or equal to (<=) and greater than or equal to (>=) operators. The Object class (which is the root of every class in C#) offers a virtual method called Equals( ). (We discuss virtual methods in 11.) If you overload the equals operator (==), it is recommended that you also override the Equals( ) method. Overriding the Equals( ) method allows your class to be compatible with other .NET languages that do not overload operators (but do support method overloading). That way, even if you can t use the == operator, you can still use the Equals( ) method to do the same thing. The Object class implements the Equals( ) method with this signature:
Code-128 Generator In Java
Using Barcode generation for Android Control to generate, create Code 128 image in Android applications.
www.OnBarcode.com
USS Code 128 Printer In VB.NET
Using Barcode creator for Visual Studio .NET Control to generate, create Code 128A image in .NET applications.
www.OnBarcode.com
public virtual bool Equals(object o)
Scan Data Matrix 2d Barcode In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Generate GS1 - 12 In .NET
Using Barcode maker for VS .NET Control to generate, create UPC Code image in .NET framework applications.
www.OnBarcode.com
From this signature, you can see that your override of this method will take an object as a parameter, and return a bool (true if the two objects are equal, where equality is however you define it). By overriding this method, you allow your Fraction class to act polymorphically with all other objects. For example, anywhere you can call Equals( ) on two Objects, you can call Equals( ) on two Fractions. Inside the body of Equals( ), you need to ensure that you are comparing one Fraction object with another Fraction object. If the other object is not a fraction, they cannot be equal, and you ll return false:
Data Matrix ECC200 Creation In None
Using Barcode creator for Word Control to generate, create Data Matrix image in Microsoft Word applications.
www.OnBarcode.com
Painting Barcode In Java
Using Barcode printer for Eclipse BIRT Control to generate, create Barcode image in Eclipse BIRT applications.
www.OnBarcode.com
public override bool Equals(object o) { if ( ! (o is Fraction) )
Painting QR Code 2d Barcode In None
Using Barcode creator for Online Control to generate, create QR Code 2d barcode image in Online applications.
www.OnBarcode.com
Code39 Printer In VB.NET
Using Barcode creation for VS .NET Control to generate, create ANSI/AIM Code 39 image in Visual Studio .NET applications.
www.OnBarcode.com
The Equals Operator |
Print Barcode In .NET Framework
Using Barcode creation for Reporting Service Control to generate, create Barcode image in Reporting Service applications.
www.OnBarcode.com
Printing Linear 1D Barcode In Visual Studio .NET
Using Barcode printer for ASP.NET Control to generate, create Linear 1D Barcode image in ASP.NET applications.
www.OnBarcode.com
{ return false; } return this == (Fraction) o; }
Create ECC200 In Objective-C
Using Barcode generation for iPad Control to generate, create Data Matrix image in iPad applications.
www.OnBarcode.com
Scan Data Matrix In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
The is operator is used to check the runtime type of an object (in this case, Fraction). Therefore, o is Fraction evaluates true if o is, in fact, a Fraction or a type derived from Fraction. Once you know that you are comparing two Fractions, you can delegate the decision as to their equality to the overloaded operator (operator==) that you ve already written, just as you did with the != operator. This allows you to avoid duplicate code. Notice, though, that before you can compare this to o, you need to cast o to a Fraction. We discussed casting with intrinsic types back in 3. In this way, the Equals( ) method determines only that you do in fact have two fractions. If so, it delegates deciding whether the two fractions are truly equal to the already implemented operator ==. The complete modification of the Fraction class is shown in Example 12-2, followed by the analysis.
using using using using System; System.Collections.Generic; System.Linq; System.Text;
namespace Example_12_2_ _ _ _Overloading_Equality { public class Fraction { private int numerator; private int denominator; // create a fraction by passing in the numerator // and denominator public Fraction(int numerator, int denominator) { this.numerator = numerator; this.denominator = denominator; } // overloaded operator+ takes two fractions // and returns their sum public static Fraction operator+ (Fraction lhs, Fraction rhs) { // like fractions (shared denominator) can be added // by adding their numerators if (lhs.denominator == rhs.denominator)
|
Copyright © OnBarcode.com . All rights reserved.