單字符變量名有哪些（不要用小寫的）？

Question

public enum DAY
{
A = 1,
B = 2,
C = 3,
D = 4,
E = 5,
F = 6,
G = 7,
H = 8,
I = 9,
J = 10,
K = 11,
L = 12,
M = 13,
N = 14,
O = 15,
P = 16,
Q = 17,
R = 18,
S = 19,
T = 20,
U = 21,
V = 22,
W = 23,
X = 24,
Y = 25,
Z = 26,
_= 27,
= 28,
= 29,
= 30,
= 31
}

Answer 1

字母 数字 下划线 不能以数字开头。貌似27个全拉