value of enum members, when some members have user-defined values.

Question

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

Are D and E guaranteed to be greater than 5 ?
Are A and B guaranteed to be smaller than 5 (if possible)?

edit: What would happen if i say C=1

Answer 1

It is guaranteed by C++ Standard 7.2/1:

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.

Answer 2

Yeah it is guaranteed and the value of A and B has to be 0 and 1 respectively.

Answer 3

In your situation, yes (see Kirill's answer). However, beware the following situation:

enum ABC
{ 
  A,
  B,
  C = 5,
  D,
  E,
  F = 4,
  G,
  H
};

The compiler will not avoid collisions with previously used values, nor will it try to make each value greater than all previous values. In this case, G will be greater than F, but not C, D, or E.