談函數(shù)指針(全局/類成員函數(shù))和函數(shù)對象

函數(shù)指針(全局函數(shù)/類成員函數(shù))、函數(shù)對象(Function object)
    一. 函數(shù)指針類型為全局函數(shù).
    以下是引用片段：
    #include "stdafx.h"
    #include
    using namespace std;
    class TestAction;
    typedef void (*fp)(int);
    void Drink(int i)
    {
    cout<<"No. "<
    }
    void Eat(int i)
    {
    cout<<"No. "<
    }
    class TestAction
    {
    public:
    fp testAct;
    void TestAct(int i)
    {
    if (testAct != NULL)
    {
    testAct(i);
    }
    }
    };
    int main(int argc, char* argv[])
    {
    TestAction doact;
    doact.testAct = &Drink;
    doact.TestAct(0);
    doact.TestAct(1);
    doact.TestAct(2);
    doact.testAct = &Eat;
    doact.TestAct(0);
    doact.TestAct(1);
    doact.TestAct(2);
    return 0;
    }
    二. 函數(shù)指針類型為類成員函數(shù).
    以下是引用片段：
    #include "stdafx.h"
    #include
    using namespace std;
    class Action;
    class TestAction;
    // 函數(shù)指針類型為類 Action 的成員函數(shù)
    typedef void (Action::*fp)(int);
    class Action
    {
    public:
    void Drink(int i)
    {
    cout<<"No. "<
    }
    void Eat(int i)
    {
    // 本文轉(zhuǎn)自 C++Builder 研究 - http://www.ccrun.com/article.asp?i=1005&d=sc37og
    cout<<"No. "<
    }
    };
    class TestAction
    {
    public:
    // 定義一個函數(shù)指針
    fp testAct;
    //Action 對象實例 , 該指針用于記錄被實例化的 Action 對象
    Action * pAction;
    void TestAct(int i)
    {
    if ((pAction != NULL) && (testAct != NULL))
    {
    // 調(diào)用
    (pAction->*testAct)(i);
    }
    }
    };
    int main(int argc, char* argv[])
    {
    Action act;
    TestAction doact;
    doact.pAction = &act;
    doact.testAct = Action::Drink;
    doact.TestAct(0);
    doact.TestAct(1);
    doact.TestAct(2);
    doact.testAct = Action::Eat;
    doact.TestAct(0);
    doact.TestAct(1);
    doact.TestAct(2);
    return 0;
    }