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C# .NET Part 7

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Flash Back

During the previous article we started to put our attention towards array in C#.NET which is one of the most important programming idioms available. Arrays will let you store large amount of data (same data type) and provides functionality to use and access them individually. Last week we an introduction was made about arrays explained the available types of arrays. And to explain the content some sample codes were given to explain it deeply.

In this article we would try to learn more about the functionalities in arrays and how the ‘array’class available in C# API could be used in our work. Furthermore we would get to know about some of the more complex data collectors such as vectors, iterations and collection types as well. We are hoping to explain them through some code examples as well. Unlike arrays which could contain only one data types, some of these data structures can contain different data types that would be huge asset when programming.

 

Array class in C#.NET

What is System.Array Class?

The type System.Array is the abstract base type of all array types. An implicit reference conversion exists from any array type to System.Array and to any interface type implemented by System.Array. An explicit reference conversion exists from System.Array and any interface type implemented by System.Array to any array type. System.Array is not itself an array-type. Rather, it is a class-type from which all array-types are derived.

The Array class, defined in the System namespace, is the base class for arrays in C#. Array class is an abstract base class but it provides CreateInstance method to construct an array. The Array class provides methods for creating, manipulating, searching, and sorting arrays.At run-time, a value of type System.Array can be null or a reference to an instance of any array type.

In the last article we discussed System.Array Class Properties. In the table mentioned below the methods which belongs to the class. The Array class provides methods for creating, manipulating, searching, and sorting arrays. Array class provides three boolean properties IsFixedSize, IsReadOnly, and IsSynchronized to see if an array has fixed size, read only or synchronized or not respectively. The Length property of Array class returns the number of items in an array and the Rank property returns number of dimensions in a multi-dimension array.

 

Method Description
BinarySearch

 

This method searches a one-dimensional sorted Array for a value, using a binary search algorithm.
Clear

 

This method removes all items of an array and sets a range of items in the array to 0.
Clone This method creates a shallow copy of the Array.
Copy This method copies a section of one Array to another Array and performs type casting and boxing as required.
CopyTo This method copies all the elements of the current one-dimensional Array to the specified one-dimensional Array starting at the specified destination Array index.
CreateInstance This method initializes a new instance of the Array class.
GetEnumerator This method returns an IEnumerator for the Array.
GetLength This method returns the number of items in an Array.
GetLowerBound This method returns the lower bound of an Array./p>
GetUpperBound This method returns the upper bound of an Array.
GetValue This method returns the value of the specified item in an Array.
IndexOf This method returns the index of the first occurrence of a value in a one-dimensional Array or in a portion of the Array.
Initialize This method initializes every item of the value-type Array by calling the default constructor of the value type.
LastIndexOf This method returns the index of the last occurrence of a value in a one-dimensional Array or in a portion of the Array.
Reverse This method reverses the order of the items in a one-dimensional Array or in a portion of the Array.
SetValue This method sets the specified items in the current Array to the specified value.
Sort This method sorts the items in one-dimensional Array objects.

Table2:Methods in System.Array class

Previously we concentrated on a code sample which was based on standard data types, but now let’s put our attention on an example which uses objects to form an array. This could very important when you are applications like games where you would need to work with number of objects.

The assignment from dogs to animals and from cats to animals is something that you definitely

can’t do in native C/C++. Arrays are assignable as long as their rank matches and the contained type is convertible from one to the other. Here both ‘Dogs’and ‘Cats’classes are derived from ‘Animals’class.

P.S:Since these are empty classes, the output won’t provide anything. These could be implemented and used in various application where handling of multiple of object sin necessary.

Figure 1:Array with Objects

 

Figure 2:Various functionalities of System.Array

·       Here an array with a fixed number of elements is created. Then with the help of an ‘if’statement that condition is checked using the ‘IsFixedSize’method. Since array has 2 elements which is a fixed value, the desired output will be displayed.

·       This is a very important method to check the stability of an array.

 

 

Figure 3:Use of Binary Search in Array class

·       In this code Binary search is used to search for the entered word. It would be search in the array. For that the ‘BinarySearch’method is used.

·       The word which needs to be searched would be entered as an object. Then it would be entered to the ‘BinarySearch’as a parameter. If the value excits in the array, zero or a positive value would be generated. If not it would be a negative value.

·       Like wise the methods which comes under ‘System.Array’can be used for various operations that needs to be done using arrays.

In the next article we would look into more data structure like Vectors, vectors are much more flexible than arrays, we would see the reason why and how it can be used in programming. Meanwhile hope that you would do more research inthese and get to know more things about arrays.

 

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Lakpriya Kottahachchi is an Undergraduate at the Faculty of Information Technology, University of Moratuwa. He enjoys programming with Java and C#.

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