From: 011netservice@gmail.com
Date: 2023-01-10
Subject: DataTypes.txt
File: CodeHelper\cs\KeyWord\DataTypes.txt

歡迎來信交流, 訂購軟體需求.


□ 以下內容以 CodeHelper\cs\KeyWord\DataTypes.txt 為準
□ C# Primitive Datatypes, 整數位數備忘:

suffix:
Binary:
int count1 = 0b_0000_0001;

Suffix type: unsigned int
Character:   U
Example:     uint x = 100U;

Suffix type: long
Character:   L
Example:     long x = 100L;

Suffix type: unsigned long
Character:   UL
Example:     ulong x = 100UL;

Suffix type: float
Character:   F
Example:     float x = 100F;

Suffix type: double
Character:   D
Example:     double x = 100D;

Suffix type: decimal
Character:   M
Example:     decimal x = 100M;



□ C# Primitive Datatypes, 整數位數備忘:
----- ----- ---------------------------- ------------------------- --------------
bytes C#                            Min                        Max 完整有效10進位
                                                                   Significant digits
----- ----- ---------------------------- ------------------------- --------------
1     byte                            0                        255              2
1     sbyte                        -128                        127              2
----- ----- ---------------------------- ------------------------- --------------
2     short                       -2^15                     2^15-1              4
2     short                     -32,768                     32,767              4
2     ushort                          0                     65,535              4
2     char
----- ----- ---------------------------- ------------------------- --------------
4     int                         -2^31                     2^31-1              9
4     int                -2,147,483,648              2,147,483,647              9
4     uint                            0                  4 billion              9
4     float                                                                     7
4     object
4     string                             length up to 2 billion bytes.
----- ----- ---------------------------- ------------------------- --------------
8     long                         -2^63                    2^63-1             18
8     long    -9,223,372,036,854,775,808 9,223,372,036,854,775,807             18
8     ulong                            0            18 quintillion             18
8     double                                                                   15
8     DateTime            1/1/01 0:00:00       9999/12/31 12:59:59
      不支援 collection 及 dictionary 的 index 
----- ----- ---------------------------- ------------------------- --------------
24    decimal                                                            28 or 29
----- ----- ---------------------------- ------------------------- --------------
8     DateTime
8     DateTime         yyyyMMddHHmmssfff                                       17
        yyyyMMdd                                                                8
        yyyyMMddHHmm                                                           14
        yyyyMMddHHmmfff                                                        17
        ticks (datatype=long, 每100奈秒為一個ticks, 從0001-01-01 00:00:00開始起算)
          A single tick represents one hundred nanoseconds or one ten-millionth of a second. 
          There are 10,000 ticks in a millisecond, or 10 million ticks in a second. 
          The value of this property represents the number of 100-nanosecond intervals that have elapsed since 12:00:00 midnight, January 1, 0001 (0:00:00 UTC on January 1, 0001, in the Gregorian calendar), which represents DateTime.MinValue. 
          It does not include the number of ticks that are attributable to leap seconds.
----- ----- ---------------------------- ------------------------- --------------
CodeHelper 交易編號:
8, long, 最大 19 位數正整數 (注意 collection 及 dictionary 的 index 只支援到 int)
4, int,  最大 10 位數正整數
8, 時間序號, 17位數, yyyyMMddHHmmssfff
8, 交易序號, 19位數, yyyyMMddHHmmssfffnn   
8, 交易亂序, 19位數, ssnnfffyyyymmddHHMM (須注意不可超過正整數上限, 即前2位正整數不可超過92)
負號的部份有一半的空間, 可再自訂規則使用.
每秒可 100,000 筆資料不重複.

交易編號優點:
1. 佔用空間小, 最多使用 8 bytes.
2. 純數字, 不會像英文字母輸入錯誤, 或大小寫輸入錯誤.
3. 可亂序或依序.
4. 以現在時間開始編號, 永遠不重複, 直到空間不夠, 可簡化維護資料庫作業.
----- ----- ---------------------------- ------------------------- --------------

 Standard Numeric Format Strings
 https://docs.microsoft.com/en-us/dotnet/standard/base-types/standard-numeric-format-strings
 int value; 
 value = 0x2045e;
 Console.WriteLine(value.ToString("x"));
 // Displays 2045e
 Console.WriteLine(value.ToString("X"));
 // Displays 2045E
 Console.WriteLine(value.ToString("X8"));
 // Displays 0002045E
 value = 123456789;
 Console.WriteLine(value.ToString("X"));
 // Displays 75BCD15
 Console.WriteLine(value.ToString("X2"));
 // Displays 75BCD15



□ 
Alias	Type Name			Type	Size(bits)	Range	Default Value
--------
sbyte	System.Sbyte	signed integer		8	-128 to 127		0
short	System.Int16	signed integer		16	-32768 to 32767	0
Int		System.Int32	signed integer		32	-231 to 231-1	0
long	System.Int64	signed integer		64	-263 to 263-1	0L  不支援 collection 及 dictionary 的 index 
byte	System.byte		unsigned integer	8	0 to 255		0
ushort	System.UInt16	unsigned integer	16	0 to 65535		0
uint	System.UInt32	unsigned integer	32	0 to 232		0
ulong	System.UInt64	unsigned integer	64	0 to 263		0

Alias	Type name		Size(bits)	Range (aprox)					Default Value
float	System.Single		32		±1.5 × 10-45 to ±3.4 × 1038		0.0F
double	System.Double		64		±5.0 × 10-324 to ±1.7 × 10308	0.0D
decimal	System.Decimal		128		±1.0 × 10-28 to ±7.9228 × 1028	0.0M
char	System.Char			16		U +0000 to U +ffff				‘\0’