C ++中函数的继承

Question

Can you help me please with this problem? I have four classes. Honeypot header:

class Honeypot
{

public:
int getNumberOfInterfaces();
Honeypot (int numberOfInterfaces);
virtual std::string typeHoneypot()=0;
protected:
    int numberOfInterfaces;
};

Honeypot.cpp:

Honeypot::Honeypot(int numberOfInterfaces){
this-> numberOfInterfaces = numberOfInterfaces;
}

int Honeypot::getNumberOfInterfaces(){
return numberOfInterfaces;
}

Class Honeypot has child HoneypotV and HoneypotN. Now I created object with number of neteorkInterfaces:

Honeypot* NetworkType::createObject(int res1, int res2, int res3) {
    if (res1 == 1 && res2 == 1 && res3 == 1) {
    HoneypotV p1(3);
    return &p1;
} else {
    HoneypotN p2(3);
    return &p2;
}

In the main function:

NetworkType select;

Honeypot *p;

p = select.createObject(1,1,1);

cout << p->typeHoneypot() << endl;
cout << p-> getNumberOfInterfaces() << endl;

typeHoneypot() is correct, but getNumberOfInterfaces() returned value -858993460, correct is 3.

Thank you for reply.

Answer 1

You returning a pointer to local variable, but when you exit from your function, all local variables will be destroyed and pointer will reference to already destroyed object

About code in main function: you declare a pointer to object and havent initialize it, so pointer points to some trash in memory

Answer 2

You should dynamiclly instanciate the object if you want to return it :

Honeypot* NetworkType::createObject(int res1, int res2, int res3) {
    if (res1 == 1 && res2 == 1 && res3 == 1) {
    HoneypotV *p1 = new HoneypotV(3);
    return p1;
} else {
    HoneypotN *p2 = new HoneypotN(3);
    return p2;
}