The use of C + + function pointers

Directory

Basic definition

Example of using C function pointers

Example of using C + + function pointers

function pointers as function arguments

function pointer as function return value

Array of function pointers

typedef simplifies function pointer manipulation

C language Function pointer definition form: return type (* function pointer name ) (parameter type, parameter type, parameter type, ...);

C + + function pointer definition form : return type (class name ::* function member name) (parameter type, parameter type, parameter type,...);

The following code compiles the environment: Codeblocks with GCC in Win 7

C language Function pointers use examples:

#include <stdio.h> #include <stdlib.h>int fun1 () {    printf ("This is fun1 call\n");    return 1;} void fun2 (int k, char c) {    printf ("This is fun2 call:%d%c\n", K, c);} int main () {    int (*pfun1) () = NULL;    void (*pfun2) (int, char) = NULL;    int a, B;    PFUN1 = fun1; The first method of assignment    a = Pfun1 ();  The first method of invocation (recommended)    printf ("%d\n", a);    b = (*pfun1) ();//The second method of invocation    printf ("%d\n", b);    Pfun2 = &fun2;//The second method of assignment (recommended because it is consistent with other data pointer assignment methods)    pfun2 (1, ' a ');    (*PFUN2) (2, ' B ');    return 0;}

Examples of using C + + function pointers:

#include <iostream>using namespace Std;class test{public:test () {cout<< "constructor" <<end    L        } int fun1 (int a, char c) {cout<< "This was fun1 call:" <<a<< "" <<c<<endl;    return A;    } void Fun2 (double d) const {cout<< "This was fun2 call:" <<d<<endl;        } Static double Fun3 (char buf[]) {cout<< "This was Fun3 call:" <<buf<<endl;    return 3.14; }};int Main () {//class static member function pointer and C pointer use the same double (*pstatic) (char buf[]) = null;//do not need to add class name pstatic = TEST::FUN3;//Can not add    Take the address symbol pstatic ("Myclaa");    Pstatic = &test::fun3; (*pstatic)    ("XYZ"); Ordinary member function int (test::* pfun) (int, char) = NULL; Be sure to add class name Pfun = &test::fun1;    Be sure to add the address symbol test mytest; (Mytest.*pfun) (1, ' a '); The call is certain to add class to the object name and the * symbol//const function (the basic ordinary member function is the same) void (test::* Pconst) (double) const = NULL;    Be sure to add a const PCONST = &test::fun2;    Test Mytest2; (mytest2.*pcOnst) (3.33);/////constructor or destructor pointers, seemingly not, do not know whether the C + + standard does not have a function pointer pointing to both//(test::* pcon) () = null;//Pcon = &test.test    ;//Test mytest3;//(Mytest3.*pcon) (); return 0;}

function pointers as function parameters:

#include <stdio.h> #include <stdlib.h>void fun (int k, char c) {    printf ("This is fun2 call:%d%c\n", K, c);} void Fun1 (void (*pfun) (int, char), int A, char c) {    pfun (A, c);} int main () {    fun1 (fun, 1, ' a ');    return 0;} C + + has the same form

function pointers as function return values:

C form # include <stdio.h> #include <stdlib.h>void fun (int k, char c) {    printf ("This is fun2 call:%d%c\n", K , c);} The argument for the FUN1 function is double, and the return value is the function pointer void (*) (int, char) void (*FUN1 (double D)) (int, char) {    printf ("%f\n", d);    return fun;} int main () {    void (*p) (int, char) = FUN1 (3.33);    P (1, ' a ');    return 0;}

C + + form # include <iostream>using namespace Std;class test{public:    int Fun (int A, char c)    {        cout< < "This was fun call:" <<a<< "" <<c<<endl;        return A;    }; Class test2{public    :    //test2 member function fun1, parameter is double,    //return value is the member function pointer of test int (test::*) (int, char)    Int ( Test::* fun1 (Double D)) (int, char)    {        cout<<d<<endl;        Return &test::fun;    }}; int main () {    test mytest;    Test2 Mytest2;    Int (test::* p) (int, char) = MYTEST2.FUN1 (3.33);    (mytest.*p) (1, ' a ');    return 0;}

Array of function pointers:

#include <stdio.h> #include <stdlib.h>float add (float a,float b) {return a+b;} float Minu (float a,float b) {return a-A;} int main () {    ///Defines a function pointer array, size 2    //Inside the float (*) (float, float) type of pointer    float (*pfunarry[2]) (float, float) = { &add, &minu};    Double k = pfunarry[0] (3.33,2.22);//Call    printf ("%f\n", k);    K = pfunarry[1] (3.33,2.22);    printf ("%f\n", k);    return 0;} C + + can be analogous

typedef simplifies function pointer type:

#include <stdio.h> #include <stdlib.h>float add (float a,float b) {    printf ("%f\n", a+b);    return a+b;} float Minu (float a,float b) {    printf ("%f\n", A-a);    return a-B;} Float (*) (float, float) typedef float (*pfuntype) (float, float) with pfuntype, int main () {    Pfuntype p = &add;// Define function pointer variable    p (3.33, 2.22);    Pfuntype Parry[2] = {&add, &minu};//defines an array of function pointers    parry[1] (3.33, 2.22);    A function pointer can be defined as a parameter: void Fun (Pfuntype p)    //function pointer as a return value can be defined as: Pfuntype fun ();    return 0;} C + + can be analogous

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Category: Basic C + +

The use of C + + function pointers