Beginner with c# 4

王朝c#·作者佚名  2006-01-08
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1¡£4 Ô¤¶¨ÒåÀàÐÍ£¨Predefined types£©

c#ÌṩÁËһϵÁÐÔ¤¶¨ÒåÀàÐÍ¡£ËüÃÇÓëc/c++Óв»ÉÙÏàËÆµÄµØ·½¡£Ô¤¶¨ÒåÒýÓÃÀàÐÍÓÐobjectºÍstring¡£

objectÀàÐÍÊÇËùÓÐÆäËûÀàÐ͵Ļù´¡¡£

Ô¤¶¨ÒåÀàÐͰüÀ¨·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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