在初始化指向成員函數的指針數組時需要一些幫助

Question

我對編程很陌生，在我正在讀的書中碰到一個程序，但遇到編譯錯誤。

錯誤顯示“可變大小的對象'ptrFunc'可能未初始化”。（它指向數組的末尾）

請告知，其中有什么問題。謝謝。

#include<iostream>

using namespace std;

class cDog
{
    public:
            void speak() const
            {
                cout<<"\nWoof Woof!!";
            }
            void move() const
            {
                cout<<"\nWalking to heel...";
            }
            void eat() const
            {
                cout<<"\nGobbling food...";
            }
            void growl() const
            {
                cout<<"\nGrrrgh...";
            }
            void whimper() const
            {
                cout<<"\nWhinig noises...";
            }
            void rollOver() const
            {
                cout<<"\nRolling over...";
            }
            void playDead() const
            {
                cout<<"\nIs this the end of little Ceaser?";
            }
};

int printMenu();

int main()
{
    int selection = 0;
    bool quit = 0;
    int noOfFunc = 7;
    void (cDog::*ptrFunc[noOfFunc])() const = {

    &cDog::eat,
    &cDog::growl,
    &cDog::move,
    &cDog::playDead,
    &cDog::rollOver,
    &cDog::speak,
    &cDog::whimper
    };

    while(!quit)
    {
        selection = printMenu();

        if(selection == 8)
        {
            cout<<"\nExiting program.";
            break;
        }
        else
        {
            cDog *ptrDog = new cDog;
            (ptrDog->*ptrFunc[selection-1])();
            delete ptrDog;
        }
    }
    cout<<endl;

    return 0;
}

int printMenu()
{
    int sel = 0;

    cout<<"\n\t\tMenu";
    cout<<"\n\n1. Eat";
    cout<<"\n2. Growl";
    cout<<"\n3. Move";
    cout<<"\n4. Play dead";
    cout<<"\n5. Roll over";
    cout<<"\n6. Speak";
    cout<<"\n7. Whimper";
    cout<<"\n8. Quit";
    cout<<"\n\n\tEnter your selection : ";
    cin>>sel;

    return sel;
}

Answer 1

void (cDog::*ptrFunc[noOfFunc])() const = {

noOfFunc不是const限定的； 您可能需要將其聲明為const int才能將其用作數組大小（在編譯時必須知道數組的大小）。

但是，當您像在這里那樣聲明一個類似於初始化程序的數組時，可以忽略大小； 編譯器將根據初始化程序中元素的數量來確定它。 您可以簡單地說：

void (cDog::*ptrFunc[])() const = {

Answer 2

`將其更改為

void (cDog::*ptrFunc[7])() const = 

要么

void (cDog::*ptrFunc[])() const =