C++指针函数，可不可以讲解下，太绕了

#include<iostream>
const double* f1(const double ar[], int n);
const double* f2(const double[], int);
const double* f3(const double*, int);
int main()
{
    using namespace std;
    double av[3] = { 1112.3,1542.6,2227.9 };
    const double* (*p1)(const double*, int) = f1;
    auto p2 = f2;
    cout << "using pointers to functions:\n";
    cout << "address value\n";
    cout << (*p1)(av, 3) << ":" << *(*p1)(av, 3) << endl;
    cout << p2(av, 3) << ":" << *p2(av, 3) << endl;
    const double* (*pa[3])(const double*, int) = { f1,f2,f3 };
    auto pb = pa;
    cout << "\nusing an array of pointers to functions:\n";
    cout << "address value\n";
    for (int i = 0; i<3; i++)
        cout << pb[i](av, 3) << ":" << *pb[i](av, 3) << endl;
    cout << "\nusing apointer to a pointer to a function:\n";
    cout << "address value\n";
    for (int i = 0; i < 3; i++)
        cout << pb[i](av, 3) << ":" << *pb[i](av, 3) << endl;
    cout << "\nusing pointers to an array of pointers:\n";
    cout << "address value\n";
    auto pc = &pa;
    cout << (*pc)[0](av, 3) << ":" << *(*pc)[0](av,3) << endl;
    const double*(* (*pd)[3])(const double*, int) = &pa;
    const double* pdb = (*pd)[1](av, 3);
    cout << pdb << ":" << *pdb << endl;
    cout << (*(*pd)[2])(av, 3) << ":" << *(*(*pd)[2])(av, 3) << endl;
    return 0;
}
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;
}

不要想复杂了，就是一个指针而已。应该说是函数指针，而不是指针函数。
本质上都是指针，只是指针的类型不一样，比如有int型 ，char型等指针，指向一个函数的指针就是函数指针。
int *p 整型指针，可以指向一个整型变量的地址。int a; p = &a
int (*p) (char * str)函数指针，可以指向一个返回整型，且有一个char *参数的函数。 int func(char * str); p = func 。要注意的就是函数指针的返回类型和参数要和指向的函数相同。