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<TD class=t1 noWrap>作者：<A
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align=absMiddle border=0> 依栏望海[17731168]</A> 2000-10-25
23:52:26 </TD>
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<TD class=content>1。4 预定义类型（Predefined types）
<BR><BR>c#提供了一系列预定义类型。它们与c/c++有不少相似的地方。预定义引用类型有object和string。
<BR>object类型是所有其他类型的基础。
<BR><BR>预定义类型包括符号数、无符号数、浮点、布尔、字符和十进制数。符号数有：sbyte、short、
<BR>int和long；无符号数有：byte、ushort、uint和ulong；浮点数有：float和double。
<BR><BR>布尔类型就像一个开关，只有两种状态：true或false。c#对布尔的要求比c/c++严格，与java类似。
<BR>在c#中false不等于0，true也不等于1；false和true都是单独分离出来的一个值。学过c/c++的网友
<BR>都知道：*/ <BR>int i = 0; <BR>if (i = 0) { // Bug: 应该是 (i ==
0) <BR>.... <BR>} <BR>/* 是没有问题的。但在c#中会引发一个编译错误（error CS0029:
Cannot implicitly convert <BR>type 'int' to
'bool'）。当然，这样牺牲了一点没有必要的灵活性。我们再也不能这样：*/ <BR>string str;
<BR>.... <BR>if(str = Console.ReadLine()) { <BR>
Console.WriteLine("Your comments are: {0}",str); <BR>....
<BR>/* 而必须：*/ <BR>using System; <BR>class BoolTest <BR>{
<BR> static void Main() { <BR> string
str = Console.ReadLine();//也可以：string str;
<BR> if(str ==
"")
// if((str =
Console.ReadLine()) == "") <BR>
Console.WriteLine("i can't read your comments. Please tell me
something! O.K.?"); <BR> else
<BR> Console.WriteLine("Your
comments are: {0}",str); <BR> } <BR>} <BR>/*
<BR>我抄了一张预定义类型的简表供大家参考。
<BR><BR>Type
Description
Examples <BR><BR>object The ultimate base
type of all other
types object o = new
Stack(); <BR><BR>string String type; a
string is a sequence
of
string s = "Hello";
<BR>
Unicode characters <BR><BR>sbyte 8-bit
signed integral
type
sbyte val = 12; <BR><BR>short 16-bit
signed integral
type
short val = 12;
<BR><BR>int 32-bit signed
integral
type
int val = 12; <BR><BR>long
64-bit signed integral
type
long val1 = 12;
<BR>
long val2 = 34L; <BR><BR>byte
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