c++ - 枚举成员的值，当某些成员具有用户定义的值时

Question

enum ABC{
 A,
 B,
 C=5,
 D,
 E
};

D和E能保证大于5吗？
A 和 B 是否保证小于 5(如果可能)？

编辑:如果我说 C=1

会发生什么

Answer 1

它由 C++ 标准 7.2/1 保证:

The identifiers in an enumerator-list are declared as constants, and can appear wherever constants are required. An enumerator-definition with = gives the associated enumerator the value indicated by the constant-expression. The constant-expression shall be of integral or enumeration type. If the first enumerator has no initializer, the value of the corresponding constant is zero. An enumerator-definition without an initializer gives the enumerator the value obtained by increasing the value of the previous enumerator by one.