vb求n阶乘表达式

Public Function N_Multiplication(ByVal n As Long) As Long '参数n为整数值，函数返回-1则表明参数n有异常，否则正常计算N阶乘数 Dim J As Long N_Multiplication = -1 '函数给定值-1，参数n必须大于等于1且不能为非数字，否则函数返回-1 If (Not IsNumeric(n)) Or (n <= 0) Th