for_each()是个function template

#include <algorithm>头文件说明

template<class _InIt,

    class _Fn1> inline

    void _For_each(_InIt _First, _InIt _Last, _Fn1& _Func)

    {    // perform function for each element

    for (; _First != _Last; ++_First)

        _Func(*_First);

    }

由以上source可知，for_each()只能配合global function和function object。

#include <iostream>

#include <stdlib.h>

#include "vector"

#include "map"

#include <algorithm>

#include <atlstr.h>

#include <xfunctional>

using namespace std;

//单一类对象

class CClassObj

{

public:

    CClassObj(void){}

    ~CClassObj(void){}

    void PrintElem(){

        std::cout << "mem_fun_ref" << std::endl;

    }

};

class ClassController

{

protected:

    vector<CClassObj> _ObjVec;

public:

    ClassController(void){}

    ~ClassController(void){}

    void AddClass(CClassObj cObj){

        _ObjVec.push_back(cObj);

    }

    void PrintElem(){

        for_each(_ObjVec.begin(), _ObjVec.end(), mem_fun_ref(&CClassObj::PrintElem));

    }

};

//多态

class AbstactClass

{

public:

    virtual void PrintElem(){

        std::cout << "Abstact mem_fun 1" << std::endl;

    }

};

class MyClass1 : public AbstactClass{};

class MyClass2 : public AbstactClass

{

public:

    void PrintElem(){

        std::cout << "Abstact mem_fun 2" << std::endl;

    }

};

class ClassCont

{

protected:

    vector<AbstactClass*> _ObjVec;

public:

    void AddClass(AbstactClass& obj){

        _ObjVec.push_back(&obj);

    }

    void PrintElem(){

        for_each(_ObjVec.begin(), _ObjVec.end(), mem_fun(&AbstactClass::PrintElem));

    }

};

struct  Mystruct

{

    int cnt;

    string str;

    Mystruct()

    {

        cnt = ;

        str = "str";

    }

};

//函数调用对象 for_each()只能配合global function和function object。

/*void Print(const Mystruct stru){ cout << stru.cnt << ", " << stru.str.c_str() << endl; }*/

void Print(const Mystruct stru, const char* str){ cout << str << stru.cnt << ", " << stru.str.c_str() << endl; }

struct PrintStru

{

    string _str = "";

    PrintStru(string str) : _str(str){

    }

    void operator()(string &str){

        cout << _str.c_str() << str.c_str() << endl;

    }

};

int main()

{

/*    Add a(1, 2), b(3, 4);*/

/*    std::cout << a << " + " << b << " = " << (a + b) << std::endl;*/

    vector<Mystruct> vecStru;

    Mystruct stru;

    vecStru.push_back(stru);

    vecStru.push_back(stru);

    /*for_each(vecStru.begin(), vecStru.end(), [](const Mystruct stru){cout << stru.cnt << ", " << stru.str.c_str() << endl; });//lambda可调用对象*/

    //Procedure Based與for_each()搭配

    /*for_each(vecStru.begin(), vecStru.end(), Print);//print： 不传入参数*/

    for_each(vecStru.begin(), vecStru.end(), bind2nd(ptr_fun(Print), "elem: "));//print：  传入参数

    //Object Oriented與for_each()搭配

    string Arr[] = { "", "", "", "", "" };

    vector<string> vecStr(Arr, Arr + sizeof(Arr) / sizeof(string));

    for_each(vecStr.begin(), vecStr.end(), PrintStru(""));//print： 不传入参数

    //若使用function object，也可以將參數傳給PrintStru()，透過constructor的技巧接收參數。

    for_each(vecStr.begin(), vecStr.end(), PrintStru("Elem: "));//print： 不传入参数

    ClassController cConT;

    cConT.AddClass(CClassObj());

    cConT.AddClass(CClassObj());

    cConT.PrintElem();

    //多态

    ClassCont cT;

    cT.AddClass(MyClass1());

    cT.AddClass(MyClass2());

    cT.PrintElem();

}