C # Learning Notes (implicit and explicit conversions, enum types, struct types, array types, and strings)

1 Type conversions

1.1 Implicit conversions : Conversions from Type A to type B can be done in all cases, and the rules for performing the transformation are simple enough for the compiler to perform the conversion.

UShort Destinationvar;

Char Sourcevar = ' a ';

Destinationvar = Sourcevar;

Console.wirteline ("Souecevar val:{0}", Sourcevar);

Console.wirteline ("Destination val:{0}", Destinationvar);

Results of the output:

Sourcevar val:a

Destination val:97

Real-time two variables store the same information, but different types interpret them in a different way.

The compiler allows the conversion of the numeric value of an implicit conversion to the following table:

Type	can be safely converted to
Byte	Short,ushort,int,uint,long,ulong,double,decimal
SByte	Short,int,long,float,double,decimal
Short	Int,long,float,double,decimal
UShort	Int,uint,long,ulong,float,double,decimal
Int	Long,float,double,decimal
UInt	Long,ulong.float,double,decimal
Long	Float,double,decimal
ULong	Float,double,decimal
Float	Double
Char	Ushort,int,uint,long,ulong,float,double,decimal

1.2 Explicit Conversions : Conversions from Type A to type B can only be done in some cases, the rules of the conversion are complex, and some type of processing should be performed.

BYTE Destinationvar;

Short Sourcevar = 7;

Destinationvar = (byte) Sourcevar;

1.2.1 Using the Convert command for an explicit conversion

Command	Results
Convert.toboolean (Val)	Val conversion to BOOL
Convert.tobyte (Val)	Val conversion to Byte
Convert.tochar (Val)	Val conversion to Char
Convert.todecimal (Val)	Val conversion to decimal
Convert.todouble (Val)	Val converts to Double
Convert.ToInt16 (Val)	Val conversion to Short
Convert.ToInt32 (Val)	Val conversion to int
Convert.toint64 (Val)	Val converts to Long
Convert.tosbyte (Val)	Val conversion to SByte
Convert.tosingle (Val)	Val conversion to float
Convert.ToString (Val)	Val converted to string
Convert.touint16 (Val)	Val conversion to UShort
Convert.touint32 (Val)	Val conversion to UINT
Convert.touint64 (Val)	Val conversion to ULONG

2 enum types

Keyword ENMU

Enmu<typename>

{

<value1>,

<value2>,

<value3>,

...

<valueN>

}

Then declare this new type

<typeName><varName>;

and assign values:

<varName>=<typeName><value>;

Note: By default, the first variable in the enumeration is assigned a value of 1, and the following value automatically adds 1

3 Structure Type

Keyword struct

struct <typeName>

{

<memberDeclarations>

}

The <menberDeclarations> section contains declarations of variables, called data members of structs, in the same format as usual. Each member's declaration takes the following format:

<accessibility><type><name>;

For the code that invokes the structure to access the data members of the structure, you can use the keyword public for <accessibility>, for example:

struct route

{

public orientation direction;

public double distance;

}

Once you have defined a struct type, you can define a variable of the new type to use the structure:

Route Myroute;

The data members in this composite variable are then accessed by the period character:

Myroute.direction = Orientation.north;

Myroute.distance = 10;

4 arrays

All of the preceding types have one thing in common: they can only store one value (the structure stores a set of values). Sometimes, you need to store a lot of data, which can cause inconvenience. Sometimes you need to store several types of the same value at the same time, instead of using a different variable for each value.

4.1 Declaring an array:

<baseType>[]<name>;

For example: int[] Myintarray;

MYINTARRAY[10] = 5;

Or: int[] Myintarray = new Int[]arraysize;

Or: int[] Myintarray = new int[5]{1,2,3,4,5}; The array size must match the number of elements

4.2 Foreach Loop

The Foreach loop can use a simple syntax to locate each element in the array:
foreach (<baseType> (name) in <array>)

{

Can usr <name> for each element

}

4.3 Multi-dimensional arrays

Two-dimensional array declaration

<basetype>[,] <name>;

Multidimensional Array Declaration

<basetype>[,,,] <name>;

5 Handling of strings

A string type variable can be viewed as a read-only group of char variables. This allows you to access each character using the following syntax:

String myString = "A string";

Char MyChar = mystring[1];

To use a string in a Foreach loop:

foreach (char character in mystring)

{

Console.wirteline ("{0}", character);

}

C # Learning Notes (implicit and explicit conversions, enum types, struct types, array types, and strings)