This document provides an overview of various C# data types and comments. It discusses basic data types like integers, floats, decimals, booleans, chars, strings, and objects. It describes characteristics of data types like name, size, and default value. It provides examples of integer types like byte, short, int, long, and float types. It also discusses strings, numbers, date times, type conversion methods, and comments in C#, including block and line comments.

1. University of Babylon
By Lecturer:
Azhar Abbas Hadi
C# Data Types and Comments
The Second Stage

2. Dаtа tyрes:
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Dаtа tyрes аre sets (rаnges) оf vаlues thаt hаve similаr сhаrасteristiсs.
Fоr instаnсe byte tyрe sрeсifies the set оf integers in the rаnge [0 …
255].
By Lecturer: Azhar A. Hadi
Сhаrасteristiсs:
Dаtа tyрes аre сhаrасterized by:
 Nаme – fоr exаmрle, int;
 Size (hоw muсh memоry they use) – fоr exаmрle, 4 bytes;
 Defаult vаlue – fоr exаmрle 0.

3. Dаtа tyрes:
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By Lecturer: Azhar A. Hadi
Bаsiс dаtа tyрes in С# аre distributed intо the fоllоwing tyрes:
Integer tyрes – sbyte, byte, shоrt, ushоrt, int, uint, lоng, ulоng;
Reаl flоаting-роint tyрes – flоаt, dоuble;
Reаl tyрe with deсimаl рreсisiоn – deсimаl;
Bооleаn tyрe – bооl;
Сhаrасter tyрe – сhаr;
String – string;
Оbjeсt tyрe – оbjeсt.

4. Strings:
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By Lecturer: Azhar A. Hadi
 A series of characters is used to store the text type data.
 It can be a character or a long paragraph.
 The size of the string can be a maximum of 2GB or 1 billion
characters. But practically it totally depends on the memory of the
computer and CPU.

5. Strings:
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By Lecturer: Azhar A. Hadi
 Use the + sign between multiple strings.
String Concatenation

6. Numbers:
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By Lecturer: Azhar A. Hadi
 In C# there are two groups of numbers
1. Integer Types
2. Float Types
1. Integer Types
Byte
Short
Int
long

7. Numbers:
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By Lecturer: Azhar A. Hadi
Byte:
 Struct is used to represent 8-bit unsigned integers.
 The Byte is an immutable value type and the range of
Byte is from 0 to 255.

8. Numbers:
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By Lecturer: Azhar A. Hadi
 Byte:
static void Main(string[] args)
{
// minimum and maximum value of Byte
Console.WriteLine("The minimum value " +
"of Byte: {0}", Byte.MinValue);
Console.WriteLine("The maximum value " +
"of Byte: {0}", Byte.MaxValue);
}

9. Numbers:
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By Lecturer: Azhar A. Hadi
Short:
 is a keyword that is used to declare a variable that can
store a signed integer value from the range -32, 768 to
32, 767. I
static public void Main()
{
// variable declaration
short number = 20;
//value
Console.WriteLine("number: " + number);
// size
Console.WriteLine("Size of a short variable: " + size of(short));
}

10. Numbers:
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By Lecturer: Azhar A. Hadi
Integer:
1- Signed Integer: A signed integer can represent both
positive and negative numbers, including zero.
 In C#, the int data type is a signed 32-bit integer, which
means it can store values ranging from approximately -2
billion to +2 billion.
 Other signed integer types in C# include short (16-bit)
and long (64-bit).

11. Numbers:
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By Lecturer: Azhar A. Hadi
Integer:
2- Unsigned Integer: can only represent non-negative
numbers (zero and positive values).
 In C#, the uint data type is an unsigned 32-bit integer,
capable of storing values ranging from 0 to
approximately 4.3 billion.
 Other unsigned integer types in C# include ushort (16-
bit) and ulong (64-bit).

12. Numbers:
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By Lecturer: Azhar A. Hadi
Integer:
Example:
static void Main(string[] args)
{
// variable declaration
int number = -245;
//value
Console.WriteLine("number: " + number);
//size
Console.WriteLine("Size of an int variable: " + sizeof(int));
}

13. Numbers:
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By Lecturer: Azhar A. Hadi
Long: is a keyword that is used to declare a variable that
can store a signed integer value from the range of
- 9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.
static void Main(string[] args)
{
// variable declaration
long number = 1234;
//value
Console.WriteLine("number: " + number);
}

14. Numbers:
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By Lecturer: Azhar A. Hadi
Float: a Float is a whole number with one or more decimal
points it can be positive or negative.

15. Numbers:
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By Lecturer: Azhar A. Hadi
Double: is a 64-bit double-precision floating-point type.
It has 14 – 15 digit Precision.
static void Main(string[] args)
{
// variable declaration
double number = 1234.123456;
//value
Console.WriteLine("number: " + number);
}

16. Numbers:
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By Lecturer: Azhar A. Hadi
Decimal: The decimal type is a 128-bit data type suitable for
financial and monetary calculations. It has a 28-29 digit
Precision.
static void Main(string[] args)
{
// variable declaration
decimal number = 1.22M;
//value
Console.WriteLine("number: " + number);
}

17. Booleans:
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By Lecturer: Azhar A. Hadi
bool: (short for Boolean) variable may be a sort of box that may hold whether
or not something is true.
static void Main(string[] args)
{
bool student_status = true;
if (student_status == true)
{
Console.WriteLine("Student enrollment is approved");
}
else
{
Console.WriteLine("Student enrollment is not approved");
}
}

18. Booleans:
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By Lecturer: Azhar A. Hadi
bool: (short for Boolean) variable may be a sort of box that may hold whether
or not something is true.
static void Main(string[] args)
{
int number1 = 20;
int number2 = 10;
Console.WriteLine(number2 > number1);
Console.WriteLine(number1 < 100);
Console.WriteLine(number1 > number2);
}

19. DateTime:
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By Lecturer: Azhar A. Hadi
DateTime: Date and Time in C# are defined by the DateTime object.

20. DateTime Format:
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By Lecturer: Azhar A. Hadi

21. DateTime Format:
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By Lecturer: Azhar A. Hadi
DateTime to String
String to DateTime

22. C# - Type Conversion:
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By Lecturer: Azhar A. Hadi
 Type conversion is converting one type of data to
another type.
In C#, type casting has two forms:
 Implicit type conversion.
 Explicit type conversion.

23. C# - Type Conversion:
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By Lecturer: Azhar A. Hadi
 Implicit type conversion: refers to the automatic
conversion of one data type to another by the compiler
when it is safe to do so.
 Typically happens when converting from a smaller data
type to a larger one.
int val1 = 10;
double val2 =val1;

24. C# - Type Conversion:
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By Lecturer: Azhar A. Hadi
 Explicit type conversion: (also known as casting) these
conversions are done explicitly by users using the pre-
defined functions.

25. C# - Type Conversion:
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By Lecturer: Azhar A. Hadi
 C# Type Conversion Methods
Sr.No. Methods & Description
1 ToBoolean
Converts a type to a Boolean value, where possible.
2 ToByte
Converts a type to a byte.
3 ToChar
Converts a type to a single Unicode character, where possible.
4 ToDateTime
Converts a type (integer or string type) to date-time structures.
5 ToDecimal
Converts a floating point or integer type to a decimal type.
6 ToDouble
Converts a type to a double type.
7 ToInt16
Converts a type to a 16-bit integer.
8 ToInt32
Converts a type to a 32-bit integer.

26. C# - Type Conversion:
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By Lecturer: Azhar A. Hadi
 C# Type Conversion Methods
9 ToInt64
Converts a type to a 64-bit integer.
10 ToSbyte
Converts a type to a signed byte type.
11 ToSingle
Converts a type to a small floating point number.
12 ToString
Converts a type to a string.
13 ToType
Converts a type to a specified type.
14 ToUInt16
Converts a type to an unsigned int type.
15 ToUInt32
Converts a type to an unsigned long type.
16 ToUInt64
Converts a type to an unsigned big integer.

27. C# - Type Conversion:
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By Lecturer: Azhar A. Hadi
 Example:
using System;
namespace TypeConversionApplication {
class StringConversion {
static void Main(string[] args) {
int i = 75;
float f = 53.005f;
double d = 2345.7652;
bool b = true;
Console.WriteLine(i.ToString());
Console.WriteLine(f.ToString());
Console.WriteLine(d.ToString());
Console.WriteLine(b.ToString());
Console.ReadKey();
}
}
}

28. Comments:
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By Lecturer: Azhar A. Hadi
 Comments in C# are the human-readable text for detailing what this
code is doing.
 In a high-level English statement, you are describing what your
program is going to do.
 They help to make your program much easier to understand.
 Use comments to keep people informed of the particular version of
the program.

29. Comments:
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By Lecturer: Azhar A. Hadi
 The comments are usually displayed in green.
We have two types:
 Block Comments
 Line Comments

30. Comments:
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By Lecturer: Azhar A. Hadi
When the C# compiler sees the "/*" sequence which means the start of
a comment it says to itself: I will ignore everything following until I see
a */ which closes the comment.
 Block Comments

31. Comments:
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By Lecturer: Azhar A. Hadi
 Another form of comment makes use of the // sequence.
 This marks the start of a comment which extends to the top of that
particular line of code.
 Line Comments

32. Next Lecture:
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C# Operators
By Lecturer: Azhar A. Hadi

33. Any questions?