05 iec t1s1 oops session 07
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Slide 1 of 32Session 7Ver. 1.0
Object-Oriented Programming Using C#
In this session, you will learn to:
Describe memory allocation
Use structure
Use enumerations
Implement arraysUse collections
Objectives
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Object-Oriented Programming Using C#
The memory allocated to variables is referred to in the
following ways:
Value types: Contains data. Built-in data types, such as int,
char, and float are value types.
Reference types: Contains address referring to a block of
memory. Data types, such as string and class are reference
types.
Let us understand the concept of memory allocation in
detail.
Describing Memory Allocation
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Object-Oriented Programming Using C#
Describing Memory Allocation (Contd.)
int Num1;
Num1=50;Initialization
Initializing Num2 with Num1
int Num2;
Num2=Num1;
Variable Declaration
Value Type:
Variable Declaration 50
50
Both Num1 and Num2 Contain 50
Num1
Num2
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Object-Oriented Programming Using C#
Describing Memory Allocation (Contd.)
Value Type (Contd.):
Num1=60;
Num1
60
Num2
50
The Value of Num2 Remains Unaffected
New Value Assigned to Num1
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Slide 5 of 32Session 7Ver. 1.0
Object-Oriented Programming Using C#
Car Suzuki= new Car();
Suzuki.Model=10;
Object of Class Car()
Member Variable of Class Car()
Initialization
Initializing Mercedes with Suzuki
Object of Class Car()Car Mercedes;
Mercedes=Suzuki;
Describing Memory Allocation (Contd.)
Reference Type:
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Slide 6 of 32Session 7Ver. 1.0
Object-Oriented Programming Using C#
Suzuki
Mercedes
***
***
10
Referring to Memory
Location Where the Data
is Stored
Referring to Memory
Location Where the Data
is Stored
Describing Memory Allocation (Contd.)
Reference Type (Contd.):
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Object-Oriented Programming Using C#
A structure is a value type data type.
When you want a single variable to hold related data of
various data types, you can create a structure.
To create a structure you use the struct keyword.
The following code shows the example of a declaring astructure names Bill_Details:
struct Bill_Details
{ public string inv_No; // Invoice Number
string ord_Dt; // Order Date
string custName; // Customer name
Using Structure
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Object-Oriented Programming Using C#
public string product; // Product Name
public double cost; // Cost of the product
public double due_Amt; // Total amount due
}
Using Structure (Contd.)
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Object-Oriented Programming Using C#
Enumeration is a value type data type.
Enumeration contains its own values and cannot inherit or
pass inheritance.
Enumerators allows you to assign symbolic names to
integral constants.To enumerate, you can use the enum keyword.
Using Enumeration
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Object-Oriented Programming Using C#
After declaring the enumeration type, you can use the
enumeration type in the same manner as any other data
type:
int First_Day = (int)Days.Sat;
int Last_Day = (int)Days.Fri;
Implementing Enumerations
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Object-Oriented Programming Using C#
Implementing Arrays
An array is a collection of values of the same data type.
The following figure shows the array structure in the
systems memory.
Index
Value 0
Index
Value 6
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Object-Oriented Programming Using C#
Declaring an Array
An array needs to be declared before it can be used in a
program.
You can declare an array by using the following statement:
datatype[] Arrayname;
Let us understand the explanation of the various elements
of the array declaration through an example.
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Object-Oriented Programming Using C#
Declaring an Array (Contd.)
int[ ] Score; Datatype
Is used to specify the
data type for the
elements
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Object-Oriented Programming Using C#
Declaring an Array (Contd.)
int[ ] Score; [ ]
Is used to specify the
rank of the array
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Object-Oriented Programming Using C#
Declaring an Array (Contd.)
int[ ] Score; Arrayname
Is used to specify the
name of the array using
which the elements of the
array will be initialized and
manipulated
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8/14/2019 05 Iec t1s1 Oops Session 07
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Object-Oriented Programming Using C#
In C#, you can initialize the array variable and can assign
values to the array elements. In addition, you can copy the
array variable to another variable.
During initialization, you need to use the new keyword to
create an instance of the array. In addition, the size of the
array is also specified while it is initialized.
The following is an example of array initialization:
int[] Score; // Array declaration
Score = new int[10]; //Array Instance
Initializing and Assigning Values to Array
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Object-Oriented Programming Using C#
When an array is initialized, you can access the element
values and manipulate them.
The foreach loop is specially used for manipulating arrays.
The following is the syntax of the foreach loop:
foreach (type identifier in expression){
//statements
}
Manipulating Array Elements
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Object-Oriented Programming Using C#
The following is the example offoreach loop:
int[] Numbers = { 4, 3, 2, 1, 0, -1, -2, 9, 5 };
Console.WriteLine("The Contents of an Array
is:");
foreach (int K in Numbers)
{
Console.WriteLine("{0} \t",K);
}
Manipulating Array Elements (Contd.)
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Object-Oriented Programming Using C#
While declaring a method if you are not sure about the
number of arguments passed as a parameter, you can use
the param array.
The following is the example ofparam array:
public int Adding_ArrayElement(params int[] List)
{
int Total = 0;
foreach ( int I in List )
{
Total += I;}
return Total;
}
Manipulating Array Elements (Contd.)
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Object-Oriented Programming Using C#
Demo: Matrix Subtraction UsingArrays
Problem Statement:
David, a student of California University, is currently pursuing
mathematics. He is working on a project named Matrix
Subtraction. He needs to perform the following tasks for his
project:
Accept data in two Arrays.
Perform the subtraction operation.
Verify the value of subtraction.
Help David to create the C# program using Visual Studio IDE.
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Object-Oriented Programming Using C#
Solution:
To solve the preceding problem, David needs to perform the
following tasks:
1. Create a console-based application for Matrix Subtraction.
2. Build and execute an application.
Demo: Matrix Subtraction Using Arrays (Contd.)
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Object-Oriented Programming Using C#
Multidimensional Arrays
The rank value of the array is also known as the dimension
of the array.
The array can be single dimensional or multidimensional.
Single dimensional array stores data in a row.
Multidimensional array stores data using differentdimensions.
The following figure is a graphical representation of values
stored in a single dimensional array and a multidimensional
array.int [] Num; int[,] Num;
0
0 1 2 3 4 1
0 1 2 3 4
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Object-Oriented Programming Using C#
Multidimensional Arrays (Contd.)
The Array class is the base class for all the arrays in C#.
The Array class provides properties and methods to work
with arrays.
Properties: The following table explains some of the most
commonly used properties of the Array class.
Properties Explanation
Length Returns the total number of items in all the dimensions of anarray
Rank Returns the total number of items in all the dimensions of anarray
IsFixedSize Return a value indicating if an array has a fixed size or not
IsReadOnly Returns a value indicating if an array is read-only or not
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Object-Oriented Programming Using C#
Multidimensional Arrays (Contd.)
Methods: The following table explains some of the most
commonly used methods of the Array class.
Properties Explanation
Sort Performs sort operation on an array passed to it as a parameter
Clear Removes all items of an array and sets a range of items in thearray to 0
GetLength Returns the number of items in an Array
GetValue Returns the value of the specified item in an Array
IndexOf Returns the index of the first occurrence of a value in aone-dimensional Array or in a portion of the Array
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Object-Oriented Programming Using C#
Using Collections
Arrays are used to collect the elements of same data type.
The .NET Framework provides several classes that also
collect elements in specialized ways. Theses classes are
the Collection classes, and are declared in the
System.Collections namespace and sub-namespaces.
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Using Collections (Contd.)
The collection classes accept, hold, and return their
elements as items.
The element type of collection class is an object. Object is a
reference type.
The following figure shows the storage of values in array oftype int:STACK HEAP
9 7 3 2
Array
@
int [] array= {9, 7, 3, 2};
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Object-Oriented Programming Using C#
Using Collections (Contd.)
The action which automatically converts the value type to
the reference type, is known as boxing.
The following figure shows the boxing technique.
STACK HEAP
@ @ @ @
Array
@
int [] array= {9, 7, 3, 2};
7 2
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Object-Oriented Programming Using C#
Using Collections (Contd.)
When you want to access the elements of an array through
its index value location in an array, use an ArrayList
class.
The following table describes the use of various methods of
an ArrayList class.
Method Use
Add Adds an object to the end of the ArrayList
Remove Removes the element at the first occurrence of a specific object from theArrayList
Clear Removes all the elements from the ArrayList
Insert Inserts an element into the ArrayList at the specified indexTrimToSize Sets the capacity to the actual number of elements in the ArrayList
Sort Sorts the elements in the ArrayList
Reverse Reverses the element in the ArrayList
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Slide 31 of 32Session 7Ver. 1.0
Object-Oriented Programming Using C#
In this session, you learned that:
Memory allocated to variables are of two types, value type and
reference type.
Value-types are the simplest types in C#. Variables of value
types directly contain their data in the variable.
Reference-types variables contain only a reference to data. Thedata is stored in a separate memory area.
A value type variable holds its value in the stack.
A reference type variable holds a reference to an object in the
heap.
To hold related data of various data type in single variable,structures are used.
C# provides the features ofenum to create user defined data
types with numbers as an index value to access them.
An array is a collection of values of the same data type.
Summary
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Object-Oriented Programming Using C#
The foreach statement interprets the common loop process
and removes the need for you to check the array size.
Param arrays are used in the methods with parameter list
when the total number of parameters is not known.
The .NET Framework provides several classes that also collect
elements together in other specialized ways. These are theCollection classes, and they live in the System
namespace.
ArrayList is useful when you want to manipulate the values
in an array easily.
Summary (Contd.)
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