Beginner with c# 4

　　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£¨

原文转自：http://www.ltesting.net