Object Oriented Programming - Value Types & Reference Types

Q3M1 – OOP C# Dudy Fathan Ali S.Kom
Value Types & Reference Types
Q3M1
Dudy Fathan Ali, S.Kom (DFA)
2015
CEP - CCIT
Fakultas Teknik Universitas Indonesia

Introduction
o The variables in a program are allocated memory at run
time in the system.
o Variables are referred in two ways, value type and
reference type.
o Value type variables contain data, whereas reference
type variables hold the reference to the memory
location where data is stored.

Describing Memory Allocation
The memory allocated to variables is referred to in two ways, value
types and reference types.
- OOP C#, NIIT Courseware MMSv2.
int Num1 = 50;
int Num2 = 100;
Example :
50
Value types are also called direct
types because they contain data.
100
Num1
Num2
Memory Allocated for Value Type Variable

int Num1 = 50;
int Num2 = Num1;
Console.WriteLine(Num1);
Another Example :
50
50
Num1
Num2

int Num1 = 50;
int Num2 = Num1;
Num1++;
Another Example :
Output:
50
50
incrementing Num1 will have no effect on Num2

class Car
{
public int Model;
public void Display_Model()
{
Console.WriteLine (Model);
}
}
class Program
{
static void Main (string[] args)
{
Car Ford = new Car ();
Ford.Model = 10;
Car Mercedes = Ford;
Ford.Display_Model();
Mercedes.Display_Model ();
}
}
Memory Allocated for Reference Type Variable
****
Ford
****
Mercedes
10
**** Output:
10
10

class Car
{
public int Model;
public void Display_Model()
{
Console.WriteLine (Model);
}
}
class Program
{
static void Main (string[] args)
{
Car Ford = new Car ();
Ford.Model = 10;
Car Mercedes = Ford;
Ford.Display_Model();
Ford.Model++;
Mercedes.Display_Model ();
}
}
Memory Allocated for Reference Type Variable
****
Ford
****
Mercedes
10
****
11
Incrementing Form.Model will changing the value
of Mercedes.Model.

Enumeration
Enumeration is a value type data type, it allows you to assign symbolic
names to integral constants.
enum Days { Sat, Sun, Mon, Tue, Wed, Thu, Fri };
To declare an enumeration type called Days, where the values are restricted to the
symbolic names of the weekdays, use the following code:
Code :
Integral
Constant
0 1 2 3 4 5 6
Symbolic
Name
Sat Sun Mon Tue Wed Thu Fri
Representation :

Enumeration
class EnumTest
{
enum Days { Sat, Sun, Mon, Tue, Wed, Thu,
Fri };
static void Main(string[] args)
{
int First_Day = (int)Days.Sat;
int Last_Day = (int)Days.Fri;
Console.WriteLine(“Sat = ” + First_Day);
Console.WriteLine(“Fri = ” + Last_Day);
Console.ReadLine();
}
}
Integral
Constant
0 1 2 3 4 5 6
Symbolic
Name
Sat Sun Mon Tue Wed Thu Fri
Full Code :
Representation :
Output:
Sat = 0
Fri = 6

Array
An array is a collection of values of the same data type. Array
elements are accessed using a single name and an index number
representing the position of the element within the array. Array is a
reference type data type.
Array Structure

Array
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 :
<data type>[] <array name>
Code Structure :
String[] DaftarNama;
Example Code :
String[] DaftarNama = new String[2];
DaftarNama[0] = “Bambang”;
DaftarNama[1] = “Suprapto”;
Initializing and Assigning Value :

Array
string[] n1 = new string[5];
Data Dalam Memori :
Data Dalam Array :
i=0
Indeks di mulai
dari 0
Assigning Value

Array
Data Dalam Memori :
Data Dalam Array :
i=0
Masuk Nilai “1”
Assigning Value

Array
1
n1[0] = “1”;
Data Dalam Memori :
i=0
a
1 a
Assigning Value

Array
1
n1[0] = “1”;
Data Dalam Memori :
i=0
a
1 a
Masuk Nilai “5”
a
Assigning Value

Array
1 5
n1[0] = “1”;
n1[1] = “5”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
a
b
Assigning Value

Array
1 5
n1[0] = “1”;
n1[1] = “5”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
Masuk Nilai “7”
a
b
Assigning Value

Array
1 5 7
n1[0] = “1”;
n1[1] = “5”;
n1[2] = “7”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
c
i=2
7 c
a
b
c
Assigning Value

Array
1 5 7
n1[0] = “1”;
n1[1] = “5”;
n1[2] = “7”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
c
i=2
7 c
a
b
c
Masuk Nilai “3”
Assigning Value

Array
1 5 7 3
n1[0] = “1”;
n1[1] = “5”;
n1[2] = “7”;
n1[3] = “3”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
c
i=2
7 c
a
b
c
i=3
d
d
3 d
Assigning Value

Array
1 5 7 3
n1[0] = “1”;
n1[1] = “5”;
n1[2] = “7”;
n1[3] = “3”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
c
i=2
7 c
a
b
c
i=3
d
d
3 d
Masuk Nilai “9”
Assigning Value

Array
1 5 7 3 9
n1[0] = “1”;
n1[1] = “5”;
n1[2] = “7”;
n1[3] = “3”;
n1[4] = “9”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
c
i=2
7 c
a
b
c
i=3
d
d
3 d
e
e
e9
i=4
Assigning Value

Array
1 5 7 3 9
n1[0] = “1”;
n1[1] = “5”;
n1[3] = “7”;
n1[4] = “3”;
n1[5] = “9”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
c
i=2
7 c
a
b
c
i=3
d
d
3 d
e
e
e9
i=4
Bisa diisi lagi?
Assigning Value

Array
1 5 7 3 9
n1[0] = “1”;
n1[1] = “5”;
n1[3] = “7”;
n1[4] = “3”;
n1[5] = “9”;
Data Dalam Memori :
i=0
a
1 a
i=1
b
5 b
c
i=2
7 c
a
b
c
i=3
d
d
3 d
e
e
e9
i=4
Tidak! Karena
Array PENUH.
Assigning Value

Array
Display Array Value
string[] n1 = new string[5]
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
Console.WriteLine(n1[i]);
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
Tampil nilai “i”
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
x = 5

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
x = 5
i=0

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
x = 5
i=0 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
x = 5
n[0] = 1i=0 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
x = 5
n[0] = 1 Tampil “1”i=0 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
n[0] = 1 Tampil “1” i = i+ 1i=0
x = 5
i < x
Y i yang baru = 1

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
x = 5
i=1 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
x = 5
n[1] = 5i=1 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
x = 5
n[1] = 5 Tampil “5”i=1 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
n[1] = 5 Tampil “5” i = i+ 1i=1
x = 5
i < x
Y i yang baru = 2

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
x = 5
i=2 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
x = 5
n[2] = 3i=2 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
x = 5
n[2] = 3 Tampil “3”i=2 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
n[2] = 3 Tampil “3” i = i+ 1i=2
x = 5
i < x
Y i yang baru = 3

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
x = 5
i=3 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
x = 5
n[3] = 8i=3 i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
8
n[3] = 8 Tampil “8”i=3
x = 5
i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
8
n[4] = 4 Tampil “4” i = i+ 1i=3
x = 5
i < x
Y i yang baru = 4

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
8
i=4
x = 5
i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
8
n[4] = 4i=4
x = 5
i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
8
4
n[4] = 4 Tampil “4”i=4
x = 5
i < x
Y

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
8
4
n[4] = 4 Tampil “4” i = i+ 1i=4
x = 5
i < x
Y i yang baru = 5

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
8
4
i=5
x = 5
i < x
N

Array
Display Array Value
n1[0] = 1;
n1[1] = 5;
n1[2] = 3;
n1[3] = 8;
n1[4] = 4;
int x,i;
x = n1.length();
i = 0;
for(i=0;i<x;i++)
{
}
Console.ReadLine();
Data array
int x,i
i++
Y
N
next
command
x = n1.length
i = 0
i < x
1 5 3 8 4
i=0 i=1 i=2 i=3 i=4
Tampil Di Layar :
1
5
3
8
4
Data telah tampil semua

Array
Latihan Mandiri
1. Buatlah array untuk menyimpan sejumlah nama siswa (jumlah
siswa berdasarkan inputan user)
2. Buatlah 2 array untuk menyimpan angka ganjil dan angka genap
dari 0 – 20 dan
3. Jumlahkanlah isi dari array ganjil dan array genap
4. Jumlahkanlah array ganjil dan genap dengan index yang sama
kemudian masukkan hasil penjumlahannya ke dalam array yang
baru
5. Hasil dari ke empat latihan di atas harus bisa ditampilkan

Thank You!
Dudy Fathan Ali S.Kom
dudy.fathan@eng.ui.ac.id
Credits array content by : Yaddarabullah S.Kom M.Kom

Object Oriented Programming - Value Types & Reference Types

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