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标题: vb.net 什么是dim [打印本页]

作者: goodday 时间: 2008-7-19 06:42 PM
标题: vb.net 什么是dim

Data Type	Size in Bytes	Description	Type
Byte	1	8-bit unsigned integer	System.Byte
Char	2	16-bit Unicode characters	System.Char
Integer	4	32-bit signed integer	System.Int32
Double	8	64-bit floating point variable	System.Double
Long	8	64-bit signed integer	System.Int64
Short	2	16-bit signed integer	System.Int16
Single	4	32-bit floating point variable	System.Single
String	Varies	Non-Numeric Type	System.String
Date	8		System.Date
Boolean	2	Non-Numeric Type	System.Boolean
Object	4	Non-Numeric Type	System.Object
Decimal	16	128-bit floating point variable	System.Decimal

dim 是用来定义一个 object 或类型

Imports System.Console
Module Module1Sub Main()
Dim a,b,c as Integer
'declaring three variables of type integer
a=10
b=20
c=a+b
Write("Sum of a and b is" & c)
End Sub
End Module

复制代码

[ 本帖最后由 goodday 于 2008-7-19 06:46 PM 编辑 ]

作者: goodday 时间: 2008-7-19 06:50 PM
你要用电脑的资源麻
你要和电脑申请咯

然后电脑会发那个空间给你
但你要讲好你要什么的空间
如 string , integer , long

如果你要很大的就申请大的

否则不够装

作者: dious 时间: 2008-7-19 07:23 PM
請問long是什么呢

作者: goodday 时间: 2008-7-19 08:13 PM

Visual Basic type	Common language runtime type structure	Nominal storage allocation	Value range
Boolean	Boolean	Depends on implementing platform	True or False
Byte	Byte	1 byte	0 through 255 (unsigned)
Char (single character)	Char	2 bytes	0 through 65535 (unsigned)
Date	DateTime	8 bytes	0:00:00 (midnight) on January 1, 0001 through 11:59:59 PM on December 31, 9999
Decimal	Decimal	16 bytes	0 through +/-79,228,162,514,264,337,593,543,950,335 (+/-7.9...E+28) † with no decimal point; 0 through +/-7.9228162514264337593543950335 with 28 places to the right of the decimal; smallest nonzero number is +/-0.0000000000000000000000000001 (+/-1E-28) †
Double (double-precision floating-point)	Double	8 bytes	-1.79769313486231570E+308 through -4.94065645841246544E-324 † for negative values; 4.94065645841246544E-324 through 1.79769313486231570E+308 † for positive values
Integer	Int32	4 bytes	-2,147,483,648 through 2,147,483,647 (signed)
Long (long integer)	Int64	8 bytes	-9,223,372,036,854,775,808 through 9,223,372,036,854,775,807 (9.2...E+18 †) (signed)
Object	Object (class)	4 bytes on 32-bit platform 8 bytes on 64-bit platform	Any type can be stored in a variable of type Object
SByte	SByte	1 byte	-128 through 127 (signed)
Short (short integer)	Int16	2 bytes	-32,768 through 32,767 (signed)
Single (single-precision floating-point)	Single	4 bytes	-3.4028235E+38 through -1.401298E-45 † for negative values; 1.401298E-45 through 3.4028235E+38 † for positive values
String (variable-length)	String (class)	Depends on implementing platform	0 to approximately 2 billion Unicode characters
UInteger	UInt32	4 bytes	0 through 4,294,967,295 (unsigned)
ULong	UInt64	8 bytes	0 through 18,446,744,073,709,551,615 (1.8...E+19 †) (unsigned)
User-Defined (structure)	(inherits from ValueType)	Depends on implementing platform	Each member of the structure has a range determined by its data type and independent of the ranges of the other members
UShort	UInt16	2 bytes	0 through 65,535 (unsigned)

msdn 的目录

作者: goodday 时间: 2008-7-19 08:20 PM
当我要存

65535 + 1 = 65536 的糖果时

我和电脑借了 char  的盒子
多了一个糖果怎么办？？

会error 咯
那你就要 string 咯

如果你要哦用

2,147,483,647  +  1000 = 2,147,484,647
integer 肯定  装不下的

那你要用 long  的 9,223,372,036,854,775,807
咯

作者: dious 时间: 2008-7-19 08:33 PM
怎么數字變化那么多
運用hex來算嗎？

作者: goodhermit95 时间: 2008-7-19 08:41 PM
简单来说，数学的代数

1+x=2
Dim x as string

1+x=2
x=textbox1.text
=)

作者: dious 时间: 2008-7-19 08:48 PM
數目怎么可以用String呢

作者: goodday 时间: 2008-7-19 09:32 PM
可以只是是当文字来处理
不能 sort 的

作者: dious 时间: 2008-7-19 09:38 PM
不、一個數學運算不可以用stringDe

作者: goodday 时间: 2008-7-19 09:43 PM

原帖由 dious 于 2008-7-19 09:38 PM 发表
不、一個數學運算不可以用stringDe

dim a as integer = 10
dim b as string = 10

dim w as integer = 100

dim c as string = a+ b
result = 1010

dm d as integer = a+b
result = error !!!

dim e as integer = a + w
result = 110

作者: dious 时间: 2008-7-19 09:47 PM
這樣就是說integer，不對馬？

作者: goodhermit95 时间: 2008-7-19 10:36 PM
我比较常用string

作者: dious 时间: 2008-7-19 10:40 PM
我不擅長programming
所以沒關系

作者: goodhermit95 时间: 2008-7-19 10:42 PM
标题: 回复 #14 dious 的帖子
那么你擅长……图片是吗，没记错

作者: dious 时间: 2008-7-19 10:44 PM
對啊
design

作者: goodday 时间: 2008-7-20 01:41 PM

原帖由 goodhermit95 于 2008-7-19 10:36 PM 发表
我比较常用string

通常是 string , integer , boolean , double 其他很少用到

作者: goodhermit95 时间: 2008-7-20 06:36 PM
标题: 回复 #17 goodday 的帖子
我不管什么都用string
不能换interger

作者: dious 时间: 2008-7-20 08:29 PM
我在java也用到String和integer

作者: goodday 时间: 2008-7-21 02:00 AM

原帖由 goodhermit95 于 2008-7-20 06:36 PM 发表
我不管什么都用string
不能换interger

string 要转 integer

dim a as string = "123"
cint(a)
or
ctype(a , integer)

作者: goodday 时间: 2008-7-21 02:00 AM
c# 的

int.parse(a);

作者: ★笨☆天使 时间: 2008-7-21 07:23 PM
半懂半不懂

我完全不会vb/c#/c++的
只是想学就下载了vb来看看
到现在什么都还写不出

只懂if,than,else
可是不懂怎样用

[ 本帖最后由 ★笨☆天使于 2008-7-21 07:57 PM 编辑 ]

作者: dious 时间: 2008-7-21 07:54 PM

原帖由 goodday 于 2008-7-21 02:00 AM 发表
c# 的

int.parse(a);

parse是什么意思呢
·

作者: goodday 时间: 2008-7-21 07:56 PM
变成或归类

作者: dious 时间: 2008-7-21 08:10 PM
想起來了
java是
parse.int

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