Help with "error: non-lvalue in unary `&'"

18 Jul 2003

      Hi,

here's the situation: I have a template class, one of its method
returns the type specified in the template (see Entry<T>::getData()).

Problem is, I can't convert its return type to pointer.
In method "cetak", the lines: "T* ptr = &(v[0]->getData())" produces
compile error: "error: non-lvalue in unary `&'".

If, I change the line to: "T* ptr = &(v[0]->data), I got no error.

===========================================
#include <iostream>
#include <vector>
using namespace::std;

template<typename T>
class Entry {
    public:
        T getData() const;
        T data;
};

template<typename T>
T Entry<T>::getData() const {
    return data;
}

typedef Entry<int> ei;

template<typename T>
void cetak(int i, const vector& v) {
    T* ptr = &(v[0]->getData());    //<------- Error here.
    //T* ptr = &(v[0]->data)      //<-------- This one success.
    cout << ptr << endl;
    cout << *ptr << endl;
}

int main() {
    vector v;

    ei* ONE = new ei();
    ONE->data = 1;
    v.push_back(ONE);

    cetak<int>(0, v);

    return 0;
}
===========================================

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