[001] Initial reference

　　A reference (reference) is the equivalent of another name for the object. The type refers to a different type. The reference identifier begins with "&".

1 int val =; 2 int &reference = val;     // Refval point to Ival 3 int &mistake;              // Error: Reference must be initialized

From the above example, you can see that the initial value is copied to the newly created object when the variable is initialized. When you define a reference, the program binds the reference to its initial value. Once the initialization of the reference is complete, the binding relationship will persist, so the reference must be initialized .

Note that a reference is an alias , and it is not an object.

1 int Ten ; 2 int &refi = i; 3 1;             // I was assigned to the 1 4 int a = refi;        // equivalent to make a = i

The initial value of the reference must be an object, and the referenced type must be strictly consistent with its object, so:

1 int &ref0;        // Error 2 Double 1.12 ; 3 int &refa = A;      // Error

[001] Initial reference