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Beginner with c# 4 (转)

原创 IT综合 作者:worldblog 时间:2007-12-02 09:04:29 0 删除 编辑
Beginner with c# 4 (转)[@more@]1¡£4 Ô¤¶¨ÒåÀàÐÍ£¨Predefined types£©

C#ÌṩÁËһϵÁÐÔ¤¶¨ÒåÀàÐÍ¡£ËüÃÇÓëc/c++Óв»ÉÙÏàËƵĵط½¡£Ô¤¶¨ÒåÒýÓÃÀàÐÍÓÐobjectºÍstring¡£
objectÀàÐÍÊÇËùÓÐÆäËûÀàÐ͵Ļù´¡¡£

Ô¤¶¨ÒåÀàÐÍ°üÀ¨·ûºÅÊý¡¢ÎÞ·ûºÅÊý¡¢¸¡µã¡¢²¼¶û¡¢×Ö·ûºÍÊ®½øÖÆÊý¡£·ûºÅÊýÓУºsbyte¡¢short¡¢
intºÍlong£»ÎÞ·ûºÅÊýÓУºbyte¡¢ushort¡¢uintºÍulong£»¸¡µãÊýÓУºfloatºÍdouble¡£

²¼¶ûÀàÐ;ÍÏñÒ»¸ö¿ª¹Ø£¬Ö»ÓÐÁ½ÖÖ״̬£ºtrue»òfalse¡£c#¶Ô²¼¶ûµÄÒªÇó±Èc/c++Ñϸñ£¬ÓëJavaÀàËÆ¡£
ÔÚc#ÖÐfalse²»µÈÓÚ0£¬trueÒ²²»µÈÓÚ1£»falseºÍtrue¶¼Êǵ¥¶À·ÖÀë³öÀ´µÄÒ»¸öÖµ¡£Ñ§¹ýc/c++µÄÍøÓÑ
¶¼ÖªµÀ£º*/
int i = 0;
if (i = 0) { // bug: Ó¦¸ÃÊÇ (i == 0)
....
}
/* ÊÇûÓÐÎÊÌâµÄ¡£µ«ÔÚc#ÖлáÒý·¢Ò»¸ö±àÒë´íÎó£¨error CS0029: Cannot implicitly convert
type 'int' to 'bool'£©¡£µ±È»£¬ÕâÑùÎþÉüÁËÒ»µãûÓбØÒªµÄÁé»îÐÔ¡£ÎÒÃÇÔÙÒ²²»ÄÜÕâÑù£º*/
string str;
....
if(str = Console.ReadLine()) {
  Console.WriteLine("Your comments are: {0}",str);
....
/* ¶ø±ØÐ룺*/
using System;
class BoolTest
{
  static void Main() {
  string str = Console.ReadLine();//Ò²¿ÉÒÔ£ºstring str;
  if(str == "")  //  if((str = Console.ReadLine()) == "")
  Console.WriteLine("i can't read your comments. Please tell me something! O.K.?");
  else
  Console.WriteLine("Your comments are: {0}",str);
  }
}
/*
ÎÒ³­ÁËÒ»ÕÅÔ¤¶¨ÒåÀàÐ͵ļò±í¹©´ó¼Ò²Î¿¼¡£

Type  Description  Examples

object  The ultimate base type of all other types  object o = new Stack();

string  String type; a string is a sequence of  string s = "Hello";
  Unicode characters

sbyte  8-bit signed integral type  sbyte val = 12;

short  16-bit signed integral type  short val = 12;

int  32-bit signed integral type  int val = 12;

long  64-bit signed integral type  long val1 = 12;
  long val2 = 34L;

byte  8-bit unsigned integral type  byte val1 = 12;
  byte val2 = 34U;

ushort  16-bit unsigned integral type  ushort val1 = 12;
  ushort val2 = 34U;

uint  32-bit unsigned integral type  uint val1 = 12;
  uint val2 = 34U;

ulong  64-bit unsigned integral type  ulong val1 = 12;
  ulong val2 = 34U;
  ulong val3 = 56L;
  ulong val4 = 78UL;

float  Single-precision floating point type  float value = 1.23F;

double  Double-precision floating point type  double val1 = 1.23
  double val2 = 4.56D;

bool  Boolean type; a bool value is either  bool value = true;
  true or false

char  Character type; a char value is a Unicode  char value = 'h';
  character

decimal  Precise decimal type with 28 significant digits  decimal value = 1.23M;

ÄãÒ²¿ÉÒÔ×Ô¶¨Òå×Ô¼ºµÄÔ¤¶¨ÒåÀàÐÍ£¬¿ÉÒÔÕâÑù£º*/
using System;
struct Digit
{...}
class Test
{
 static void TestInt() {
  int a = 1;
  int b = 2;
  int c = a + b;
  Console.WriteLine(c);
 }
 static void TestDigit() {
  Digit a = (Digit) 1;
  Digit b = (Digit) 2;
  Digit c = a + b;
  Console.WriteLine(c);
 }
 static void Main() {
  TestInt();
  TestDigit();
 }
}
/*
ÕâÒ»½ÚÓеã³ÁÃÆ¡££º£¨


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