溢出异常? [英] Overflow exception?

问题描述

我有以下代码可用于查找阶乘:

I have the following code for finding factorials:

Private Shared Function Factorial(ByVal Number As Long) As Long
        If Number = 0 Then
            Return 1
        Else
            Return Number * Factorial(Number - 1)
        End If
End Function

通常会导致溢出.仅当我从4之类的小内容开始时才起作用.

It usually results in an overflow. It only works if I start with something small like 4.

我必须使用30-60之类的起始号码.

I have to work with starting numbers such as 30-60.

有什么想法吗?我认为将值类型更改为LONG可以避免此问题.

Any ideas? I thought changing the value type to LONG would prevent this problem.

这是VB.net，仅供参考.

This is VB.net just for reference.

推荐答案

框架变得非常大，非常快. Long中可容纳的最大数字约为9×10 ^ 18.阶乘(30)约为2.7×10 ^ 32.

Factorials get very large, very quickly. The largest number that will fit in a Long is about 9×10^18. Factorial(30) is about 2.7×10^32.

如果您使用的是.Net 4，则有一个内置的

If you're using .Net 4 there is a built-in BigInteger class that you can use which will hold arbitrarily large numbers.

如果您未使用.Net 4，则需要查找并下载BigInteger库，例如 intx .

If you're not using .Net 4, you'll need to find and download a BigInteger library, for example intx.

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