Arrays, Multidimentional Arrays, Jagged Arrays, Structures and Enums

1. Bhushan Mulmule
bhushan.mulmule@dotnetvideotutorial.com
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2. For video visit
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3. Agenda
 Single Dimensional Array
 Array Class
 Array of Reference Type
 Double Dimensional Array
 Jagged Array
 Structure
 Enum
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4. Array
 Data structure holding multiple values of same data-type
 Are reference type
 Derived from abstract base class Array
20 50 60
0 1 2
Arrays are zero
indexed
Last index is always
(size – 1)
5000
5000
marks
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5. Array Declarations
// Declare a single-dimensional array
int[] array1 = new int[5];
// Declare and set array element values, Size can be skipped
int[] array2 = new int[] { 1, 3, 5, 7, 9 };
// Alternative syntax. new keyword can be skipped
int[] array3 = { 1, 3, 5, 7, 9 };
// Declaration and instantiation on separate lines
int[] array4;
array4 = new int[5];
5000
5000
array1
0 1 2 3 4
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6. 0 0 0
int[] marks = new int[3];
Console.WriteLine("Enter marks in three subjects:");
for (int i = 0; i < 3; i++)
marks[i] = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Marks obtained:");
Console.WriteLine("Printed using for loop");
for (int i = 0; i < 3; i++)
Console.WriteLine(marks[i]);
Console.WriteLine("Printed using foreach loop");
foreach (int m in marks)
{
Console.WriteLine(m);
}
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5000
5000
marks
The default value for elements
of numeric array is zero
0 1 2
Single Dimensional Array
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7. Array Class
 Base class for all arrays in the common language runtime.
 Provides methods for creating, manipulating, searching, and
sorting arrays
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8. Array Class
int[] numbers = { 78, 54, 76, 23, 87 };
//sorting
Array.Sort(numbers);
Console.WriteLine("sorted array: ");
for (int i = 0; i < numbers.Length; i++)
Console.WriteLine(numbers[i]);
//reversing
Array.Reverse(numbers);
...
//finding out index
int index = Array.IndexOf(numbers, 54);
Console.WriteLine("Index of 54: " + index);
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9. Array of Reference Types
static void Main(string[] args)
{
string[] computers = { "Titan", "Mira", "K computer" };
Console.WriteLine("Fastest Super Computers: n");
foreach (string n in computers)
{
Console.WriteLine(n);
}
}
2000 2200 1800
Titan
Mira
K Computer
2000 1800
2200
5000
5000
Computers
Note: Default value for elements
of reference array is null

10. int[,] marks = new int[3, 4];
for (int i = 0; i < 3; i++)
{
C.WL("Enter marks in 4 subjects of Student {0}", i + 1);
for (int j = 0; j < 4; j++)
{
marks[i, j] = Convert.ToInt32(Console.ReadLine());
}
}
0 0 0 0
0 0 0 0
0 0 0 0
40 50 60 70
80 90 70 80
30 50 80 70
0
1
2
0 1 2 3
2D Array
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11. Console.WriteLine("---------------Score Board------------------");
for (int i = 0; i < 3; i++)
{
Console.Write("Student {0}:tt", i + 1);
for (int j = 0; j < 4; j++)
{
Console.Write(marks[i, j] + "t");
}
Console.WriteLine();
} 0 0 0 0
0 0 0 0
0 0 0 0
40 50 60 70
80 90 70 80
30 50 80 70
0
1
2
0 1 2 3
2D Array
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12. Jagged Array
 Array of Arrays: A jagged array is an array whose elements are
arrays.
 The elements of a jagged array can be of different dimensions
and sizes.
 Syntax:
type[][] identifier = new type[size][];
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13. Jagged Array
int[][] a = new int[3][];
a[0] = new int[2] { 32, 54 };
a[1] = new int[4] { 78, 96, 46, 38 };
a[2] = new int[3] { 54, 76, 23 };
2000
1800
2200
5000
5000
a
2000 2200 1800
32 54 54 76 23
78 96 46 38

14. for (int i = 0; i < 3; i++)
{
for (int j = 0; j < a[i].Length; j++)
{
Console.Write(a[i][j] + "t");
}
Console.WriteLine();
}
2000
1800
2200
5000
5000
a
2000 2200 1800
32 54 54 76 23
78 96 46 38

15. Struct
 Keyword to create user defined datatype
 Typically used to encapsulate small groups of related variables
 A struct type is a value type
 Structs can implement an interface but can't inherit from
another struct or class.
NOTE: structs can contain constructors, constants, fields, methods, properties,
indexers, operators, events, and nested types, although if several such members are
required, consider making your type a class instead.

16. struct Point
{
public int x;
public int y;
}
class Program
{
static void Main(string[] args)
{
Point p1;
Console.WriteLine("Enter X and Y axis of point:");
p1.x = Convert.ToInt32(Console.ReadLine());
p1.y = Convert.ToInt32(Console.ReadLine());
C.WL("Coordinates of p1: x = {0}, y = {1}", p1.x, p1.y);
Console.ReadKey();
}
}
0 0
p1
x y
10 20
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17. Enum
enum Gender
{
Male,
Female,
Other
}
Gender g1 = Gender.Female;
1
g1
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18. Enums
 The enum keyword is used to declare an enumeration, a distinct
type consisting of a set of named constants called the
enumerator list.
 The default underlying type of the enumeration elements is int.
 By default, the first enumerator has the value 0, and the value of
each successive enumerator is increased by 1.
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19. enum Gender
{
Male = 10,
Female,
Other
}
class Program
{
static void Main(string[] args)
{
Gender g1 = Gender.Female;
C.WL("g1 represents {0}. But value stored is {1}", g1, (int)g1);
Gender g2 = Gender.Male;
C.WL("g2 represents {0}. But value stored is {1}", g2, (int)g2);
}
}
11
10
g1
g2
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20. Bhushan Mulmule
bhushan.mulmule@dotnetvideotutorial.com
www.dotnetvideotutorial.com