C ?????

1
C?????
2
?????(variable)?

• ???????????
• ????????????
• ??????????
• ????
• ???????
• ?????
• ??????

??????? ???????????
3
Literal Constant

• 20???????
• 20 //???????
• 024 //??????? (???)
• 0x14 //????????
• ???0?????,???0x?????.

example
4
Literal Constant

• ?? (123) int
• ????? 20u ? 20U
• ??? (?????????) 222222222L
• ?????? 222222222uL
• ??? (3.14) float ? double
• ???? 3.14E-3 (0.00314) ? 4E2 (400)
• ???float?? 1.0f ? 1.0F
• ??????? 3.14159L

?? unsigned
?? long
5
???? (Literal Constant)
char (????) short, int ,long (????) float,
double, long double (???)
Literal Constant
?????
?? int x20 // (10??) short
y024 //(???) long z 0x14 //(16??) (1024L)
?? gt int ??
??? float x20.1f // (10??) (3.14f) double
y20.1
?? f ?????? double ?
6
????
???????
char ??????? 1 Byte(1 machine byte)
short int ??? 2 Bytes
int ?? 4 Bytes(1 machine word)
long int ??? 4 Bytes (32??? int)
float ?????? 4 Bytes
double ?????? 8 Bytes
long double ????? ? Bytes (?sizeof??)
bool ??? 1 Byte
?? 8 bit
????? short
?? 16 bit
unsigned ??? unsigned int signed ??? signed int
?? 32 bit (???? int)
????? long
Note long double????????????? ??? VC, BCB, g
7
????????????
????
?????
??????
?????
????????????
ms-help//MS.MSDNQTR.2004JAN.1033/vclang/html/_plu
slang_fundamental_types.htm
8
????(32??????)

• sizeof(Type) ??Type??????,?Byte???.
• ???? DemoTypeSize.cpp link
• ????
• char -gt -128127
• int -gt
• unsigned char -gt 0255
• unsigned int -gt 02?32??-1
• unsigned??????.

9
??????
include ltiostreamgt include ltlimitsgt
// for numeric_limits using namespace std void
main() cout ltlt "largest int" ltlt
numeric_limitsltintgtmax() ltlt endl cout ltlt
"largest float" ltlt numeric_limitsltfloatgtmax()lt
lt endl cout ltlt "largest unsigned
int"ltltnumeric_limitsltunsigned intgtmax()ltlt
endl
numeric_limits
ms-help//MS.MSDNQTR.2004JAN.1033/vcstdlib/html/vc
lrf_limits_Numericlimits_class.htm
10
???? (Literal Constant)
char (????)
???? a 2 ???? ?????? \n ?? ASCII??
\7 (bell) ? cout ltlt \7 \14
(new line) ??? La ?? Hello World \n
null ??????
C-style?? Hello World \n \0
???????
11
??
????????
?? ???? (???) Example main() char x
char ya float pi3.14f ???????? int
x1,y2 //???? int x(1) //??x1
?C????,?? Statement????? ??
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???Object????(??)

• ????
• char a
• int day
• unsigned int year
• ????????
• char a,b,c
• int year,day
• unsigned int id,count

• ??
• global?????0.
• local???????.
• ???? VarDemo.cpp link

13
??
??????
int f(int arg) // f ???
prototype void main() int x ,
y1 xy //??x1 x // xx1 x-- //
xx-1 x4 // xx4 int zf(x) int f
(int arg) return arg1
14
???????
void
15
????(??)

• outline
• ?????
• ???????
• ????
• Why Pointer

16
????(??)-- ?????

• ????????
• int y5

ProgramGetAddress
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????(??)-- ??????

• ?????
• ????????????
• int x // ???????????????
• double y //??????double???????
• Ex
• int y5 // ?????? y , ???? 5
• int x // ???????? x, ????????
• xy // ? y ????? x???.
• int pyy // ????? y ????? py ???
• y ? x? py? py?

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????(??)-- Why Pointer?

• ?????
• ???????copy
• ??????
• char A100
• char pAA0
• (pA1)???A1
• ???????????
• Div2(int x)
• pDiv2(int x)

C type?????????? const char strHello
const char kk20Hello
19
????
???????? char x // x???????? int y
// y???????? // ??
?????????? int y5 int x //??????????? xy
// ???y???,??x? cout ltlt x coutltlt y
20
????
?? int y5 int xy
x???1202????? ??? 5
21
??????
int ip1 int ip2 int var32 ip1var ip2ip1
coutltltip2 ??32 ????PointerDemo.cpp
03A9
ip1
03A9
32
var
22
????
int A100 // ??????,???A,???100 int
pointerA0 //????????????
1
2
100
(pointer0)
(pointer1)
(pointer99)
???? PointerArrayExample
23
????????? string ? char
?????????????,???????????.
This is a book \0
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????

• ??C ???????--C??????????
• ????
• int lengthstrlen (This is a book)
• ?
• char mesg100this is a book
• int lengthstrlen(msg)
• 2. Assignment???? astrthis is a book
• strcpy(astr,this is a book)
• 3. ????
• strcat(string1,string2)
• ????????????????,????????(buffer overflow)?
• Ex char str201 // \0 ?

25
String Class

• C Standard Library?????????Class.
• ??? string ????.
• ????StringClassDemo.cpp
• ?????C Standard Library,?????????? using
  namespace std ?????.

26
String type ????

• string type ??????????????
• string str1(This is a book) //????????
• ????
• int lengthstr1.size()
• 2. Assignment
• str2str1 // ?java ??
• 3. ????
• str3str1str2
• 4. ???C-style ??
• const char cstr1str1.c_str()
• 5. ????
• str10 str11 . str1length

Or str1.length()
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??

• 01DebugStringClass
• ???ioStreamDemo
• ??????,????????

28
String type ????
????? c-style ??????
???cout ??? c-style string
includeltiostream.hgt include ltstringgt using
namespace std void main() string a cout ltlt
"?????" ltlt endl cingtgta
// error string b"StringB" cout ltlt b
// error
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• ?? reference
• ??????(alias),??????object??????.
• ????????object??.
• int a
• int ba
• int c see ReferenceDemo.cpp

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const???

• ??????Object???????,???????????.
• Ex
• void main()
• const int a //???????.
• const int b70 //??
• b123 //??const????????.

Try ok
31
Array type ????

• Definition
• ????????????objects???
• ????object?????index ???????
• ???????
• int a10 char b13 float c3
• (index0 9)
• Access object??
• int ta0 a3a7 coutltlta9

Array type ????
32
Array type ????
????????? int a31,2,3 const int
bCount4 int bbCount11,12,13,14 int
c21,22,23,24,25

• ???? ArrayInit.cpp

33
Multidemension??

• 2??? Definition
• ???????
• int a23 float b34 char
  t313
• Access ?????
• coutltlta00 a12a02 b120.38f
• ???????
• int a230,1,2,
• 3,4,5

Program Array2DDemo.cpp
34
????????????

• ??int a5??,????a,???a??????????????. (ex)
• an ???n???????????.
• ??
• a0???a0???,a3???a3???
• (a2)???a2???,?a2??a02
• ????ArrayPointerDemo.cpp

35
??(Enumeration)??

• Definition (?????????)
• ???enum
• enum ??
• ??
• ?
• enum MyDataType A1, B2, C3
• Usage
• MyDataType xxyy A
• MyDataType yy(MyDataType)(AB)
• ???????,?????????0????1??.
• ????????.

??? 1,?? A C
??(Enumeration)??
?????,?????

• Program example
• EnumDemo.cpp.

36
Typedef

• Definition
• ???typedef
• ???????????????????
• Ex
• typedef int Integer
• void main()
• int a10
• Integer b23
• coutltltabltltendl

• TypedefDemo.cpp

37
End
??? debut.cis.nctu.edu.tw/ching
38
??

• ?? C ??????????,?????????.
• ?? c-style ?? ?? string ??
• ????, ????, ????, ??????????

int x // ???? xx1 // x ?????,??? x char
strJing cout ltlt str