[C++] Rebinding a reference is not allowed

As described in the title, c++ doesn't allow to rebind a reference. See some sample code.

int a = 1;
int b = 2;

int &ref = a;
ref = 5;
cout << a << " " << b << endl; // 5 2

ref = b;
ref = 6; 

cout << a << " " << b << endl; // 6 2

We try to rebind the ref to variable b and update the value of b through reference. But it doesn't work.

Here is a explanation about this and very easy to understand.

Update

Thanks @l1048576 's comment. In C++11 there is a class std::reference_wrapper that wraps a reference in a copyable, assignable object.

int a = 1;
int b = 2;
std::reference_wrapper<int> ref = a;
ref.get() = 3;
cout << a << " " << b << endl; // 3 2

ref = b;
ref.get() = 5;
cout << a << " " << b << endl; // 3 5