Java Programmer learns C + + 's function pointers

The definition of a function pointer:

Header file: Function.h

The header defines the interface, defines the template method in the actual source file//The subsequent calling class only needs to implement a callback that overrides the Before,process,after method to implement the template method/*extern can be placed before a variable or function, To indicate the definition of a variable or function in another file, prompting the compiler to find its definition in other modules when it encounters this variable or function. */extern void (*before) (), extern void (*process) (int,int), extern void (*after) (), void my_function (int a,int b);

Source file Main.cpp

#include "function.h" #include <iostream>using namespace Std;extern void Dosth ();// The static tag for the method is scoped to the module (file) in the static void Before_pro () {cout << "Main.before_pro" << Endl;} static void Process_pro (int a, int b) {cout << "Main.process_pro" << Endl;} static void After_pro () {cout << "Main.after_pro" << Endl;} void My_function (int a, int b)//{//before ();//process (A, b);//after ();//}int Main () {before = Before_pro;process = Process_pro;after = after_pro;my_function (2,3);d osth (); return 0;}

Source file: Test.cpp

#include <iostream> #include "function.h" using namespace Std;void (*before) (); void (*process) (int, int); void (* After) (); static void Before_pro () {cout << "Test.before_pro" << Endl;} static void Process_pro (int a, int b) {cout << "Test.process_pro" << Endl;} static void After_pro () {cout << "Test.after_pro" << Endl;} void Dosth () {before = Before_pro;process = Process_pro;after = After_pro;my_function (2, 3);} void My_function (int a, int b) {before ();p rocess (A, b); after ();}

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Java Programmer learns C + + 's function pointers