[英]Need some help with initializing an array of pointers to member functions
我对编程很陌生,在我正在读的书中碰到一个程序,但遇到编译错误。
错误显示“可变大小的对象'ptrFunc'可能未初始化”。(它指向数组的末尾)
请告知,其中有什么问题。谢谢。
#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;
}
void (cDog::*ptrFunc[noOfFunc])() const = {
noOfFunc
不是const限定的; 您可能需要将其声明为const int
才能将其用作数组大小(在编译时必须知道数组的大小)。
但是,当您像在这里那样声明一个类似于初始化程序的数组时,可以忽略大小; 编译器将根据初始化程序中元素的数量来确定它。 您可以简单地说:
void (cDog::*ptrFunc[])() const = {
`将其更改为
void (cDog::*ptrFunc[7])() const =
要么
void (cDog::*ptrFunc[])() const =
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