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class Base {
public:
	virtual void func(void) {
		cout &lt;&lt; &quot;Base&quot; &lt;&lt;<< "Base" << endl;
	}
};

class Derived : public Base {
public:
	int i;
	Derived() { i = 0; }

	void func(void) {
		cout &lt;&lt; &quot;Derived &quot; &lt;&lt;<< "Derived " << ++i &lt;&lt;<< endl;
	}
};

void walk(class Base *bar, int count) {
	for (int i = 0; i &lt;< count; i++) {
		bar[i].func();
	}
}

int main(void) {
	Base dis[3];
	Derived dat[3];

	walk(dis, 3);
	walk(dat, 3); // crashes
}

void walk(class Base *bar [], int count) {
	for (int i = 0; i &lt;< count; i++) {
		(bar[i])-&gt;func>func();
	}
}

int main(void) {
	Base* dis[3] = {new Base, new Base, new Base};
	Base* dat[3] = {new Derived, new Derived, new Derived};

	walk(dis, 3);
	walk(dat, 3);
}

void walk(vector&lt;Base*&gt;barvector<Base*>bar) {
	for_each (bar.begin(), bar.end(), mem_fun(&amp;Base::func));
}

int main(void) {
	vector&lt;Base*&gt;vector<Base*> dis(3);
        for (int i=0; i&lt;3i<3; i++) dis[i] = new Base;

	vector&lt;Base*&gt;vector<Base*> dat(3);
        for (int i=0; i&lt;3i<3; i++) dat[i] = new Derived;

	walk(dis);
	walk(dat);
}