Underlying type

Context: Enums have an underlying integral type (default is int). You can change it to byte, sbyte, short, ushort, int, uint, long, or ulong.

public enum SmallEnum : byte
{
    Zero = 0,
    One = 1,
    Max = 255
}

Specifying underlying type

public enum FileMode : uint
{
    Read = 1,
    Write = 2,
    ReadWrite = 3
}

Real-world usage example

Memory‑sensitive applications: Use byte as underlying type for enums with less than 256 values to save memory when stored in large arrays.

Example: In game development, a WeaponType : byte enum reduces memory footprint for thousands of enemies. Enum.GetUnderlyingType can be used to inspect.

Related sections

• 6.3 Enums
• 6.3.1 enum definition