Structure (struct)

This lesson describes the structure syntax and the difference between it and the class. U/K) S
_ V) C *] (}. @
The following two examples are given. The first example describes how to use the structure. The second example describes how to transmit an instance to sgbfq6a 'B ^ 6?
Method
Di7zh9axu8s
The differences between structures and classes also involve the following concepts.
4 V/Dita ^ /{
* Structure and class
Hhvtj % ~ BK
Z
Tkp
* Heap and stack
0/8rw0 /~ Id _
* Construct and inherit! Rpioq5uc & D
* Attribute (attributes) and structure L & | # J "P. o
Example 1 me-'_-WC; @ 1i
The following example declares a structure with three members: an attribute, a method, and a private domain.
| {Xfui4ut; Z
000: // structs/struct1.cs nv1wd; V] % i0vq
001: using system;
Triel "m
002: struct simplestruct D8 ^ Cz6M-u % B
003 :{
E) S (KS
K
004: Private int xval;
# Dw1enzk 'pd
005: Public int x
% -[}
NW/Q
006 :{
'W @ k8u7b 'z J
007: Get {
& T9dnx: pw! U'
008: Return xval; (Y. v @; mm {./% [
009 :}
QX
Od, v5u "e6cd
010: set {5 @ ^
| 9y n2c
011: If (value <100) ^ vab1al: R
012: xval = value;
NWA
J
L
013 :}& ^ (lobby: Is
014:} 8 _ | + _: wbo2s]
015: Public void displayx ()
/Q'jd9f) d
016: {-US * J. H: I; A m
017: console. writeline ("the stored value is: {0}", xval); 9A on (| @ 8ahu? &
018 :}
{
F, B [EJ o
019 :}
0p7d
T4 ^ X,}/-P %? I
020:
-C7ig ^ *~ /Y3t
021: Class testclass Q
Cr (}! PIR "}-n
022: {PE) E % [0iq "x
023: public static void main ()
+ J7 _ +] V ,? Mn8ss
024 :{
^/RL
T9i ~ 4d3f {Ki
025: simplestruct Ss = new simplestruct ();-G ^ 2bw ', W
Y J! N6s
026: SS. X = 5;
, Ggtq-BCU
027: Ss. displayx ();
@ R3f & k2y1jpn
028 :}
5_t "/T # lhcf-^ 1N
029:} lo | syjw
Output result kc3h7epsz3w
U
The stored value is: 5, vvk + I $ H | 1 m/5 K
[Structure and class]
+ D % v8j3oxp
The structure can be seen as a class, but it is different from the class, the class is a reference type, and the Structure
I5? /I1d7s3z # O $ oo_a
^ J4h! Do 'R. c
Is the value type. You can also use the structure to define the type object so that it looks like the built-in type. @ T # yp
Dyn _
[Heap and stack]: rn & donr % B # VJ * k/h
When you use the new operator for the class, it allocates space from the heap. However, when you instantiate a structure, it is in the heap

Cy + r3l
'Nw '@
Stack
+ M (ED
GQ @. s '@ Zn
In this way, the performance will be different. Moreover, you cannot handle structure instance references like the operation class.
CSF (] 6i + w-U + }{
Because
/{7ljr, FN DZ
Therefore, when a structure is passed through a parameter, it is passed through a value instead of a reference., qb3w
Dtlo
Example 2 Z & day3 @
In this example, the structure is passed as a parameter, while the class is passed by reference.
: Zhl?
DF
F
000: // structs/struct2.cs
(O, BHW r9zt
001: using system;
Y8pa % Hu
002: % czfiw. {* F: W
TX
003: Class theclass u
C: qu0 _ j * F: ^
004: {"/. E & No: f}
005: Public int X;
HI7Tnu-P 8n}
006 :}
SM 'jguw Z $ y
007:. B };@
C
E # Rb
008: struct thestruct
* R5kv; njwb! S & R} NV
009: {. jj3ty7 {EZ) E
Z-J @
010: Public int X;
2L [Z-E $ o9g, Su
011:} 7 @) ey, I % a2bb C
012 :.? 'Iu '9eqm
013: Class testclass
6 njzb; f3a: gp ~
Y
014: {ef1iap $ C % jhh1g $ m
015: public static void structtaker (thestruct s) * x] 4 H * {n1wl
016: {m9z "} 9_r4yd; t
017: S. x = 5;
G #? 4O * ^ &? @ W
018:} iz; czni
U/1f]
019: public static void classtaker (theclass C)
8jq} H % '. P "c8b
020: {& L} 3tp/LD
@/TV
021: C. x = 5;
4bk3h6z-y
022 :}
% Y/4fnfj6r]
023: public static void main () "gix {: Tg
S
024: {l5j (B, ^ # Wem]
025: thestruct A = new thestruct ();
] 8xk ~ A "a3cy * WI
026: theclass B = new theclass (); 9C! D5bzb;/J
027: A. x = 1;
2jk/Z ^ TJ # bm7p
028: B. x = 1; *] (JP
Wu
029: structtaker ();
0ne | bpi4/"d
030: classtaker (B );
3gt #} t5c
031: console. writeline ("A. X = {0}", A. X); VQ. g9ctfjof-{. c
032: console. writeline ("B. x = {0}", B. X); G ~ U) J (@ o | TX
033 :}
% GH 'o # wk % BS {
034:} 8/) E (_ d) r
Output result s |! J] 1u
Y
A. x = 1
"Szgzy) y #@
B. x = 5
# C9k
~ : FT-Co (u * d
Code Discussion
& A, mmwuw
The above example shows that when the structure is passed as a parameter, a copy is generated, and the class is different, and 3i3iy 'd n inside the method & |
Pair
Di-/ np3kv
Class instance direct reference. 8j5 {7xy-s/
Construction and inheritance: l3zk
O (M
] 4xm5x
The structure can also have constructors, but the constructor must have parameters. The constructor without parameters is
B, 'n9d "H * Fe # u
Error ox4 ~ 3 ~ S
Structure members cannot be initialized. A structure constructor is usually used to initialize its members. V @; Oct
When you use the new operator to create a structure, the appropriate constructor will be called. However, unlike the class
^ 7zs0h7a % s] T
Yes, O (B. u2l ~ "Q6p4u
The structure can be initialized using the new operator. If you do not use new, the structure domain will not be initialized. 3 P ~ PW s! T]
The structure cannot be inherited or inherit other structures and classes, and it cannot be the base class of the class. However, the structure can be $ C hmu5n $] k0md
Follow
, Z + BG "} K % j0z
The following code demonstrates the implementation of a structured interface.
Lgssh7z] m
Interface iimage
8 [o $ Y _} 4rq) Zn
{@ HB "O] J $ J, c1j $ k5x
Void paint (); X & ^ 9vck /? ADU
} Tusms5my $ L
Struct picture: iimage
H {+ cyy? I * wkim
{
+ Q0n' ^ ~ 6tzr: E
Public void paint ()
: Cql (D * F $ A/VR _
{
Do5 @ 2bi & og % cs8p
// Painting code goes here
Wavevpp0rmq "G Y
} _] 5S
} XC! T
Private int x, y, z; // other struct members
D8o/{P-LZ "pf %]
}
; Z7iew1i/@'m
Attribute and structure ix4x % XG + u5w! E
The attribute can be used to determine the structure distribution in the memory. For example, you can use
V) HKC-/F
The structure of the structlayout (layoutkind. Union) attribute generates a combination similar to that in C/C ++, RH:/p r; t
Using system. runtime. interopservices;: l "J" F! | J
[Structlayout (layoutkind. Union)]

Hz .~ Bi *]
Struct testunion ij5by $ m) I $ P. G; d | I
{E! L) n? /VK-_ c
Public int I;
0b: LM */|
Public double D;
2O % HQ, kja7}
Public char C;
{'{9wz! W $ gp8d/L C
Public byte B1;
# | 5olh {o
}
9 ?, Q/^ s _ [& z9m K
All fields in testunion start from the same space address.
Xunpd1y @/n8ck
You can also use structlayout (layoutkind. explicit) and fieldoffset to specify [/Code]