函数指针高级使用

/**********************************************************************
* 版权所有 (C)2017, Wang maochun。
*
* 文件名称：arfupt.c
* 文件标识：无
* 内容摘要：该程序参考C++primer plus，主要熟悉函数指针的使用 
* 其它说明：[] ()的优先级比*高 
* 当前版本：V1.0
* 作    者：Wang maochun
* 完成日期：2017.7.24
*
**********************************************************************/

#include <iostream>
//various notations ,same signature

const double *f1(const double *ar,int n);
const double *f2(const double ar[],int n);
const double *f3(const double ar[],int n);


int main()
{
    using namespace std;
    double av[3] = {1112.3,1542.6,2227.9};
    
    //pointer to a function
    const double *(*p1)(const double *,int) = f1;
    auto p2 = f2; //C++11 automatic type deduction
    //pre-C++ can use the following code instead
    //const double *(*p2) (const double *,int) =f2;
    cout << "Using pointers to functions:
";
    cout << "Adress Value
";
    cout << (*p1)(av,3) << ":" << *(*p1)(av,3) <<endl;
    cout << p2(av,3) << ":" << *p2(av,3) <<endl;
    
    //pa an array of pointers
    //auto doesn't work with list initialization
    const double *(*pa[3])(const double *,int) = {f1,f2,f3};
    //but it does work for initializing to a single value
    //pb a pointer to first element of pa
    auto pb = pa;
    //pre C++11 can use the following code instead
    //const double *(**pb)(const double *,int) = pa;
    cout <<"
Using an array of pointers to function:
";
    cout << "Address Value
";
    for (int i = 0; i<3;i++)
        cout << pa[i](av,3) <<":" << *pa[i](av,3)<<endl;
    cout <<"
Using a pointer to a pointer to a function:
";
    cout << "Adress Value
";
    for (int i = 0; i<3;i++)
        cout << pb[i](av,3) <<":" << *pb[i](av,3)<<endl;
    
    
    //what about a pointer to an array of function pointers
    cout << "
Using pointers to an array of pointers:
";
    cout << "Adress Value
";
    //easy pc =&pa;
    auto pc = &pa;
    //pre-C++ can use the following code instead
    //const doubel *(*(*pc)[3])(const double *,int) = &pa;
    cout << (*pc)[0](av,3) << ":" <<*(*pc)[0](av,3) <<endl;
    //hard way to declare pd
    const double *(*(*pd)[3])(const double *,int ) =&pa;
    //store return value in pdb
    const double * pdb = (*pd)[1](av,3);
    cout << pdb <<":"<< *pdb <<endl;
    //alternative notation
    cout << (*(*pd)[2])(av,3) <<":"<< *(*(*pd)[2])(av,3)<<endl;
    
    //cin.get();
    return 0;
    
} 

//some rather dull functions
const double *f1(const double *ar,int n)
{
    return ar;
}

const double *f2(const double ar[],int n)
{
    return ar+1;
}

const double *f3(const double ar[],int n)
{
    return ar+2;
}

运行结果：

小技巧：如何定义该函数指针变量？ 将函数声明中的函数名通过*p替代

              [] ()优先级比*高

　　　　该程序每隔几天多读读，简直是指针与函数结合最难的。

Dev C++ 支持C++11 ：先在dev的【工具】里找到【编译选项】，在这个【编译时加入以下命令】处打钩,然后在空白栏输入【-std=c++11】,确定.然后就能支持c++11