C # getting started with the classic note _ Chapter3 _ variables and expressions

C #

Chapter 3:

3.1 C #

1. No matter whether the Code contains spaces, carriage returns, or

3.2

1. Yes. Different types of data must be processed in different ways. Variables are limited to different types to avoid confusion between them. For example

2.

3.2.1

1. A simple type is the type of basic components in an application, such as numeric values and boolean values.

2. Simple types are different from complex types, and there cannot be child types or attributes.

3. The reason why there are too many numeric types is that numbers are used as a series

4. Value Type table:

Integer:

Type	Alias	Allowed value
Sbyte	System. SByte	In
Byte	System. Byte	In
Short	System. Int16	In
Ushort	System. UInt16	In
Int	System. Int32	In
Uint	System. UInt32	In
Long	System. Int64	In
Ulong	System. UInt64	In

Floating point:

Type	Alias
Float	System. Single
Double	System. Double
Decimal	System. Decimal

Character:

Type	Alias	Allowed value
Bool	System. Boolean	True/flase
Char	System. Char	One
String	System. String	A group of characters

Note:

1.

2. string

 

3.3.2

The basic naming rules are as follows:

1. the first character of the variable name must be a letter, underscore, or

2. The subsequent characters can be letters, underscores, or numbers.

Microsoft

For simple variables, use

 

3.3.3

Escape Sequence

Escape Sequence	Generated characters	Character
\'	Single quotes	Zero x 0027
\"	Double quotation marks	Zero x 0022
\\	Backslash	0x005C
\ 0	Null	Zero x 0000
\	Warning (generate beep)	Zero x 0007
\ B	Return	Zero x 0008
\ F	Form feed	0x000C
\ N	Line feed	0x000A
\ R	Enter	0x000D
\ T	Horizontal Tab	Zero x 0009
\ V	Vertical Tab	0x000B

Notice

Unicode

For example, "wyh \'s blog" is equivalent to "wyh \ u0027s blog"

 

3.3.4

1. Declare multiple variables of the same type at the same time.

Int xsize, ysize;

 

3.4

1.

3.4.1

1. + var1 =-var2; // var1 = var2 *-1

Var1 = + nar2;

+

2. Pair

3. Char

4. String

5. Increment and decrease operators:

Operator	Category	Example	Result
++		Var1 = ++ var2	Var1
--		Var1 = -- var2
++		Var1 = var2 ++
--		Var1 = var2 --

1. ++

2 .--

 

3.4.2

=

 

3.4.3

Priority	Operator
High	++
	*
	+
To	=
Low	++

 

3.4.4

1. The name is uniquely defined by the namespace.

Namespace levelone

{
// Name "namethree" defined

Namespace leveltwo
{

// Name "namethree" defined

}

}

2. using

Namespace levelone

{

Using levelone;

Namespace leveltwo

{

// Name "namewo" defined

}

}

Levelone