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Beginner with c# 4

2006-09-21

1?£4 ?¤?¨ò?ààDí£¨Predefined types£? c#ìá1?á?ò??μáD?¤?¨ò?ààDí?£?ü??ó?c/c++óD2?éù?à??μ?μ?·??£?¤?¨ò?òyó?ààDíóDobjectoístring?£ objectààDíê??ùóD????ààDíμ

1?£4 ?¤?¨ò?ààDí£¨Predefined types£?

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objectààDíê??ùóD????ààDíμ??ù′??£

?¤?¨ò?ààDí°ü਷?o?êy?¢?T·?o?êy?¢??μ??¢2????¢×?·?oíê?????êy?£·?o?êyóD£osbyte?¢short?¢
intoílong£??T·?o?êyóD£obyte?¢ushort?¢uintoíulong£???μ?êyóD£ofloatoídouble?£

2???ààDí?í??ò????a1?£???óDá???×′ì?£otrue?òfalse?£c#??2???μ?òa?ó±èc/c++????£?ó?javaàà???£
?úc#?Dfalse2?μèóú0£?trueò22?μèóú1£?falseoítrue??ê?μ¥?à·?à?3?à′μ?ò????μ?£?§1yc/c++μ?í?ó?
???aμà£o*/
int i = 0;
if (i = 0) { // Bug: ó|??ê? (i == 0)
....
}
/* ê???óD?êìaμ??£μ??úc#?D?áòy·¢ò???±àò?′í?ó£¨error CS0029: Cannot implicitly convert
type int to bool£??£μ±è?£??a?ù?téüá?ò?μ???óD±?òaμ?áé??D??£?ò???ùò22??ü?a?ù£o*/
string str;
....
if(str = Console.ReadLine()) {
Console.WriteLine("Your comments are: {0}",str);
....
/* ??±?D?£o*/
using System;
class BoolTest
{
static void Main() {
string str = Console.ReadLine();//ò2?éò?£ostring str;
if(str == "") // if((str = Console.ReadLine()) == "")
Console.WriteLine("i cant read your comments. Please tell me something! O.K.?");
else
Console.WriteLine("Your comments are: {0}",str);
}
}
/*
?ò3­á?ò????¤?¨ò?ààDíμ??ò±í1?′ó?ò2????£

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
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