帽子^运算符与Math.Pow() [英] Hat ^ operator vs Math.Pow()

问题描述

仔细阅读了 ^(帽子)运算符和

Having perused the MSDN documentation for both the ^ (hat) operator and the Math.Pow() function, I see no explicit difference. Is there one?

显然有一个区别，一个是函数，而另一个被认为是运算符，例如这将不起作用:

There obviously is the difference that one is a function while the other is considered an operator, e.g. this will not work:

Public Const x As Double = 3
Public Const y As Double = Math.Pow(2, x) ' Fails because of const-ness

但这会:

Public Const x As Double = 3
Public Const y As Double = 2^x

但是它们产生最终结果的方式有所不同吗?例如，Math.Pow()是否进行更多的安全检查?还是其中一个只是别的别名?

But is there a difference in how they produce the end result? Does Math.Pow() do more safety checking for example? Or is one just some kind of alias for the other?

推荐答案

一种找出方法是检查IL.对于:

One way to find out is to inspect the IL. For:

Dim x As Double = 3
Dim y As Double = Math.Pow(2, x)

IL是:

IL_0000:  nop         
IL_0001:  ldc.r8      00 00 00 00 00 00 08 40 
IL_000A:  stloc.0     // x
IL_000B:  ldc.r8      00 00 00 00 00 00 00 40 
IL_0014:  ldloc.0     // x
IL_0015:  call        System.Math.Pow
IL_001A:  stloc.1     // y

对于:

Dim x As Double = 3
Dim y As Double = 2 ^ x

IL 也是:

IL_0000:  nop         
IL_0001:  ldc.r8      00 00 00 00 00 00 08 40 
IL_000A:  stloc.0     // x
IL_000B:  ldc.r8      00 00 00 00 00 00 00 40 
IL_0014:  ldloc.0     // x
IL_0015:  call        System.Math.Pow
IL_001A:  stloc.1     // y

IE编译器已将^转换为对Math.Pow的调用-它们在运行时相同.

IE the compiler has turned the ^ into a call to Math.Pow - they're identical at runtime.

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