class C {
private:
int n{ 5 };
public:
int return5() { return 5; }
void f(int d = return5()) {
}
void ff(int d = n) {
}
};
Why I can't initialize the functions default parameters with member class? I get an error: a nonstatic member reference must be relative to a specific object.
I think the problem because no object has been instantiated yet, but is there any approach to do it?
The default argument is considered to be provided from the caller side context. It just doesn't know the object on which the non-static member function return5 could be called on.
You can make return5 a static member function, which doesn't require an object to be called on. E.g.
class C {
...
static int return5() { return 5; }
void f(int d = return5()) {
}
...
};
Or make another overload function as
class C {
private:
int n{ 5 };
public:
int return5() { return 5; }
void f(int d) {
}
void f() {
f(return5());
}
void ff(int d) {
}
void ff() {
ff(n);
}
};
return5and notreturnN? As you can see,return5is not too bad. Thevoid f(int d = n)hinted at in the question title...