Default constructor that calls peer constructor with unique_ptr move - c++

Question

I am trying to make a class with two constructors. One that is a default constructor, the other calling the parameterized constructor. I get a compiler error that tells me that I cannot use move on the object just created and I sort of understand that it doesn't like to do that, because there is no real assignment here.
How can I achieve the right behavior? I am trying to avoid writing two constructors that initialize the variables. An initialization function might work, but then I would have to fill the body of the constructors and I was trying to come up with a neat solution like shown below.
#include <string>
#include <iostream>
#include <memory>
using namespace std;
class Foo
{
public:
Foo(unique_ptr<int>& number) : m_number(move(number))
{
}
Foo() : Foo(make_unique<int>(54))
{
}
void print()
{
cout << m_number << endl;
}
private:
unique_ptr<int> m_number;
};
int main()
{
Foo f;
f.print();
return 0;
}
main.cpp:18:33: error: invalid initialization of non-const reference
of type ‘std::unique_ptr&’ from an rvalue of type
‘std::_MakeUniq::__single_object {aka std::unique_ptr}’
Foo() : Foo(make_unique(54))

Answer 1

I decided to go for an rvalue constructor. This seems to resolve the issue for me.
#include <string>
#include <iostream>
#include <memory>
using namespace std;
class Foo
{
public:
// rvalue constructor so that we can move the unique_ptr.
Foo(unique_ptr<int>&& number) : m_number(move(number))
{
}
Foo() : Foo(make_unique<int>(54))
{
}
void print()
{
cout << *m_number << endl;
}
private:
unique_ptr<int> m_number;
};
int main()
{
Foo f;
f.print();
unique_ptr<int> a = make_unique<int>(33);
Foo f2(move(a)); // important to do a move here, because we need an rvalue.
f2.print();
return 0;
}