From 9f6088a31e80fb0056a2947b754413cfcfe4328e Mon Sep 17 00:00:00 2001 From: xliu79 Date: Sat, 18 Jul 2020 23:30:56 +0800 Subject: [PATCH] english --- english/basic_content/c_poly/README.md | 46 +++++++++++++++++ english/basic_content/c_poly/c++_examp | Bin 0 -> 8720 bytes english/basic_content/c_poly/c++_examp.cpp | 43 ++++++++++++++++ english/basic_content/c_poly/c_examp | Bin 0 -> 8720 bytes english/basic_content/c_poly/c_examp.c | 55 +++++++++++++++++++++ 5 files changed, 144 insertions(+) create mode 100644 english/basic_content/c_poly/README.md create mode 100755 english/basic_content/c_poly/c++_examp create mode 100644 english/basic_content/c_poly/c++_examp.cpp create mode 100755 english/basic_content/c_poly/c_examp create mode 100644 english/basic_content/c_poly/c_examp.c diff --git a/english/basic_content/c_poly/README.md b/english/basic_content/c_poly/README.md new file mode 100644 index 0000000..59e7c6a --- /dev/null +++ b/english/basic_content/c_poly/README.md @@ -0,0 +1,46 @@ +# Object oriented features of C + + implemented by C + + +## About Author： + + +![](../img/wechat.jpg) + +## 1.C++ + +Polymorphism in C ++ :In C++, we usually maintain a virtual function table. According to the assignment compatibility rule, we know that the pointer or reference of the parent class can point to the child class object + + + +If the pointer or reference of a parent class calls the virtual function of the parent class, the pointer of the parent class will look up its function address in its own virtual function table.If the pointer or reference of the parent object points to an object of a subclass, and the subclass has overridden the virtual function of the parent class, the pointer will call the overridden virtual function of the subclass. + +Code Example:[c++_examp.cpp](./c++_examp.cpp) + + + +## 2.C Implement + +- Encapsulation + +There is no concept of class class in C language. But with struct structure, we can use struct to simulate； + +Encapsulating properties and methods into structures using function pointers. + + + +- Inherit + +Structure nesting + + +- Polymorphic + +Class and subclass methods have different function pointers + +There is no member function in the structure of C language. How to realize the common function of parent structure and child structure? We can consider using function pointers to simulate. But there is a flaw in this approach：The function pointer between the parent and child does not point to the virtual function table maintained in C ++, but a piece of physical memory. If there are too many simulated functions, it will not be easy to maintain. + +In order to simulate polymorphism, function pointer variables must be aligned(They are completely consistent in content and alignment of variables).Otherwise, the parent class pointer points to the child class object, and the operation crashes! + + + +Code example :[c_examp.c](./c_examp.c) diff --git a/english/basic_content/c_poly/c++_examp b/english/basic_content/c_poly/c++_examp new file mode 100755 index 0000000000000000000000000000000000000000..fe986fd26f303345cb71edb58a029c5bf9672f44 GIT binary patch literal 8720 zcmeHMU2Igx6`tMoAAjqG@M9n<+XN~T)yo=;YoIN6*K2c4*WhA1r7GsK_O9(M_O7*i z*EKw}R0b4_kXUL|Syd}VY5JEwREd!4hqi#+hD2&5r)v7pCX!1_Y7$66w8$^8{m$Gu z`*Xc+qDp7a5iwYp+xHMTq+$u3&P_CI*DLof>8LlR$1vEJ|Sz!LS1)~LvI6~soUY;~nwD_l0 z1I&f+%6hV+SUqkjf}fBD=Kfq9Rz2GhOm?-(u2$JGpH+b|=l)UO=;~5_yPO&%k~Lx? zB=31nxWp?Gg&!;Yb7 z-B3J{8LJy>YOHH)@THT!owDELpL7o#>Xt3>IC>#b|JLH79H9EwLIa1s)BSFAZglUy zz3;BSy=TXd{bb7*iXWR+KyytAZHlK9{>dfqUBJD#77_a0N8M}`BN;O-3?pqu`c4{s zgC~vtNPGwYX%Lz+jp0Z<0c2n}nNWx!4uso+&Bjh&L$0*bw;RnkF&-*eAURN`{_{Mo zjmKBfhy@jv*%V(!Hetv_3)LqirySs1BA~`|f|#hpMgEw)1$e$yT9t zl>cUhSLo-inC0`GsL{uNT{XiR7SHZ}4Jz4fmvFD%qM=0cAXVO+%YwGOLNbMNb5_bP zkxU`nydvdZ$o-RKKvaLbZQ`xt`owj8{BL(Uy4tQ?Ia8qt{n}NJWY?z4H8KBl82+=r zdP_)%=>zCMw_c}#>EjD-ed5OG=4tXoVXyAFOcmKVD4!)z^vqC{{XUj|MfKhKH$RjP zu0C|Zfj)6ZzdFBPcf78@_0U|G^R|M$Rd0bGtNk;dySdyeL}qn24CfOFtmpOeKLT>x zlPz8L;sv6Q?-!Z!555JvoU^-Rke%(hc^WoUzWf4uIRA@>+3aM`j09dH;HP;2bK;Nc z7s|HPq9gi5%R>DX{aVZHw=pE(b3Y<}v1JZ5ck~N%d1PzZ-&>7dXkUoxyH-kTOlU70 zzc~~5QsC*pL^jYJ=n7xl_F<(LgK@ErcxT(h{kDm>!`pAjT)6tcHUIYq*{put1a6DklOyjFGAB?19 z-oW0y{h37Vb`grD;-j&sH^_i+Yd1HX=5Tmrub{s-_fN)7O1 z;A@d}zXd-APVXNg$LS-&G3Ie>URhZ+>8SJ&PT!no;O{9?P*hr9h^?q6{VM2dr0e#y zx@!(rulQQk8L@xUzNdC=eS%=p3E}z_;#y5W!0kEjY+h9nM#B)PK8kC@f2co;`YO~P z1<%<#JEa5i{W2~M^)adsx;@W3gYKH=TrFEg_StgX?LS|kyPL)<+ud5q-4t;9 z1Mb?O+Y3GD2i;Y2TyDX95Pk~Z3*_<WBk*Vh9*w~N?+A=w(LmIpxD;^XwIlPD zs-m_`lO-%pC7rF%B;RO>xqa4VCG-A>x05w$KSkd^BCh|}!)%h|DW^s(x99V_ESc81 zMAJ@0FLdb6;%Crw4s8v5e2D)gPsgWr&m=O7D)6pHcM+{+~16$J!g}SMxfm_<6cSclzra{f+)Tb{}@xg=}kbYIa!ekGe|YE@76$ z%X0Zs=*)#|nl7ndAvnK^^(#fGd2u0Ir%KG13#TKT7sY;-=kli*Um^H8D#llejuPYU z605{yN!*<~w<-2hE%>=C#yw(EJ+H<1YMei4g^(<}u!CMGi9eQm&I^rPSWWWtU5u|2 zv<7aq|12Q{s!q^R)8A?`?>Z&g1S7i|6GB zz)SUOss8><`dK4tt2C7I^h*>=jRR?v^8cnZeQZ%a{7L#*Jnw&1`g}eoMcnSo!s7f~ zh7LGN<%^`F~V(~U4|i|u~cjzo;G7C!yGpHhLVXG zo%%(S#=uarH!@^I&15QVL^5NdFF8Ci6fN+#wIEM5`_dWN0b#UtwHx`N z>1uDLf$56$4#niTsHX8TCmn9KW)cBm#G(;10#C&Urg=>oG27W`zLMNv)ZxK8NQF>z zs*1XF(in^+qKLp~I}EL8JYi(gF^oVycp3o;CkU`NomRfAW7>nG#t}8u%|nrNTFx_i z#)C{<=3FT1u<)f%4V#f(a5H7`K`zA;$ea=3OC-&hFA!|2Ga~~^8c1Y(y_qe%9%8H8H z?L)xtV=d3^PdPQIIi&!OpZ{U;zCkMCb_f^kUD$rwsX?NBj$~rYV)CC9^_}f&6#g_g z?QPhe*Ry`L;W?`GnAykgI4Wpw!uGuGeMZ^yK8xdLJ?1B2PkSAfd3`*k?ER|Y3h=`C z6)b2yLu1PJypDcD*>gX+eS81UD*K>vIOo!2X-?Ve3MYH=Ww(D07{x{L5%IdbR!ubT zTdmr~`7?ovLVI4ncPM*}4Hf7AJIr6O+4DMoQrUC7?8YvC&t}ix;}@0vbqcP4xLt<6 zk3wPmyl*(G288#utgqa%D1M^sdH#4^F{$jI%xPK$yZx&+d)|le|IpA!*k88U^L}MP zwclXtzkU2@ol3uYRl4N%HT-|nu5XuVeN8QS&LaIm>>0U*pCC)?AX+CpM`=Cr=$whQ$_>OgEI sE2>JHDBI>|r_g>(#m~>tCs4Tq7x#zXi}ZY!YQIVyV13r++}{4b0pHwq(EtDd literal 0 HcmV?d00001 diff --git a/english/basic_content/c_poly/c++_examp.cpp b/english/basic_content/c_poly/c++_examp.cpp new file mode 100644 index 0000000..aee979b --- /dev/null +++ b/english/basic_content/c_poly/c++_examp.cpp @@ -0,0 +1,43 @@ +/** + * @file c++_examp.cpp + * @brief c++中的多态 + * @author 光城 + * @version v1 + * @date 2019-08-06 + */ + +#include + +using namespace std; +class A +{ + public: + virtual void f()//Implement a virtual function + { + cout << "Base A::f() " << endl; + } +}; + +class B:public A // 必须为共有继承，否则后面调用不到，class默认为私有继承！ +{ + public: + virtual void f()//Virtual function implementation, virtual keyword in subclass can not be appearence + { + cout << "Derived B::f() " << endl; + } +}; + + +int main() +{ + A a;//Base class object + B b;//an object of derived type + + A* pa = &a;//The parent class pointer points to the parent object + pa->f();//Call the function of the parent class + pa = &b; //The parent class pointer points to the subclass object, which is implemented in polymorphism + + + pa->f();//Call the function with the same name of the derived class + return 0; +} diff --git a/english/basic_content/c_poly/c_examp b/english/basic_content/c_poly/c_examp new file mode 100755 index 0000000000000000000000000000000000000000..458fb2a5db728b32f9b99b15c7b598fb0f65583a GIT binary patch literal 8720 zcmeHMU2Igx6`tMoAAjqGKw=;&+XN&N$(J=4*O0c{UH@=R*WemEO;yZg?Ooej>|Ja3 zE;XoXQyFM1LSm^^<(En*C9Rr1G^vnksXsv6hD4&3(* z0COSyvYzZHR-adj;74SEc_0^uUC(v|lU=Q{t5tT)XH{U#xqs9*db*Y0ZnqAJWSy93 zk?%YwU82rwR+P$bQlpaVMSLl{&%;icNd1p``IJJJYHz8$+*JKzu0*kIINsOTux&V6 zHylr7#_GnJ8tWPxv~*J2F8fXXNq6u59@!G-(GQ9Gw-yi00jmFI`-7sPg(;7PRF>k|~tyvr>MZ zWD4Q>B`Nno9+)HpqWTZoC*C-0O#HADOk6v*ahg0)*sFUlQbl$S$|ngFy)zW$fX4DKslLbf#^0oa z%lABRU`*UJF3;~VT(25$+_To@yscnw)tlhQZvUyzTwm@NBD1;&hVuyo*86Jt9{{;- z%a$(sv49xkdqk%E{cpi8=j;|4WM_M?pMVXOFJ3?o=YM`Lo1N^Pk-#ei{3s7#Oaf8k zOxc!Nbi|lwU8uigTxp&C4pIU>_XFZ*TW3*o(>OzqPqvo*9niVOs2$3gj)kbPW2N+o zVGg6Y*Jtwi34S5?L~tS->c;0RKJs zo8a$&e+YgESzn7;c@_K+IIT}at`l9tHRf||Tv=H)>8kV*PQOV*@b?%gC@QTl#Aei! z{`|kQS)FvfzBX^ozUmcUsd`H6+3@&dJ2pQ;FzK}5sX#od2?%<9r`^q~D#B41En$D_l4jOs&P-*fJex8_+-tJiISULl62PZjF7MO*4BXGa{S4gC!2fRsMzLui z>Qr0`c=6tm`ASt$Tc*nrHm8!#SLl+jx5eB!Yon6+e8k7e8g-tc-!~$z|Hr*-lH@73 zPAqrk3wUgq_PIpUZk?D|F5f~tsW_bjh-z#m)+x>`x3|T1kBEQE3@PP*|7j0F^pMTO zoNAx(*Obh0b9>mFOJW&6mv(=YKDHTBb}7A^N`6|^EBJrT_#EqOXh4nYF~v_S?$q1c z+`QXg+tZgxSQ-CLtw9UaHD;t#|F!x?EzqFV*Kf5e{M!Tdje*9%E~gKt?7?hna_df5 zo{zdq;vQj@#LIH?r_h-PvuV1deud!qRjgkrN{x#LvvsP(czJL;!t-DaKa_ z{*H?Am7=pm-aTTKm@J8VbN4pIeyRn3m&LeGyrjO@Vth63AM`>@ zg+?Ci7Ww-w#@7it206(i9>hIMDg2?_`L@u;LtnT0ev9$-B2W_FAm~`8Nel9}?TqWkiCg5w3f4Vgw;&px-aKA)~U*DJb;`#GA>8Dtiq+W@81s%GH z&Gfz*oE1izdhX{|(`Yl-GeW zW%o94${Ss?5Xmzm_*-~7~T3sljh)XvM(}hMy+HjZALOM zBFD{G!b%+%1F6VJ%#3D6MvlXzKr*3e6{+@{v9ZX=s0^{KE7;L$w(f61jCR0WE;5S> zv*nBXgB|V7&?=~r_mhBd|7x}xrtQsW=@RDN@PSY;Y#wN9JJ{N7b_YY@R%$`sYWAly zvID|w@9r@3sp;-$ro?nd`i5ijUR2llnv*U!+cJruFk{h(6@jPX3)8$NWz2DRny(}` z$T~dO7pV}6ZdFm2PMSlJL=+L2?FXP0jVH`ZI))77gQpBoI3a+2>9q1?U(@b8W_GEe zZXS-L({h~AGfpyfndd@LhlQ3tK4L}sz^#U} zeVI6}(Bn~|ku(%Z4+$-LJOO_;w^DY^u~;e{PbP{46LqQBaD)t0X>`~Un(U*7qBfX> zXvN0xrfCPIq#Oe+Hl!xnP!vvBvQ6z7XIpUj%l%M8Gm(*aKVnE)F}vdEPJb|1kbSWt4fnW4IoLLVMm< zTFT*OR#e<+-vay&_VV2Rlv|gYQwret%O#pW? zLmxG$fjU<}&iv6n)r&_>m)yCA{~vYgJ7wA*RTtRv`KN}Qf}HwJ`Onay5V?ImXZSy+ z{kyQGRI@#wr}+QtS=E0v9JzRS9!xpf=l>NKs8b+kyeu>SJ9G-;7rakY4Fsf@{EO|F zFF5RZe;ZKt94C8VJC^UEKp6L*_l3GLbn2^gu(|L6Aj}yj+tWX_g~ayEX@ARY7wWaB w3$c}~s45+zY@5HGLi;fl|D+nYPoQ!e9_|mXi}Zb#YQIWdV13%*+}Zwr0KepfGXMYp literal 0 HcmV?d00001 diff --git a/english/basic_content/c_poly/c_examp.c b/english/basic_content/c_poly/c_examp.c new file mode 100644 index 0000000..7798d3e --- /dev/null +++ b/english/basic_content/c_poly/c_examp.c @@ -0,0 +1,55 @@ +/** + * @file c_examp.c + * @brief C实现多态 + * @author 光城 + * @version v1 + * @date 2019-08-06 + */ + +#include + +/// Define a pointer of function +typedef void (*pf) (); + +/** + * @brief parent class + */ +typedef struct _A +{ + pf _f; +}A; + + +/** + * @brief child class + */ +typedef struct _B +{ + A _b; ///< The inheritance of the parent class can be realized by defining an object of the base class in the subclass +}B; + +void FunA() +{ + printf("%s\n","Base A::fun()"); +} + +void FunB() +{ + printf("%s\n","Derived B::fun()"); +} + + +int main() +{ + A a; + B b; + + a._f = FunA; + b._b._f = FunB; + + A *pa = &a; + pa->_f(); + pa = (A *)&b; /// The parent class pointer points to the object of the subclass. Because of the type mismatch, it needs to be forced + pa->_f(); + return 0; +}