Initialization of a constant reference with a number [duplicate]
Solution 1:
A non-const reference cannot point to a literal. You cannot bind a literal to a reference to non-const (because modifying the value of a literal is not an operation that makes sense) and only l-values can be bound to references to non-const. You can however bind a literal to a reference to const.
The "const" is important. In this case, a temporary variable is created for this purpose and it's usually created on stack.