Math.Pow is not calculating correctly

c# pow
Olivier_s_j picture Olivier_s_j · Nov 28, 2010 · Viewed 7.9k times · Source

I'm having a problem with C#. To be precise with the Math.pow(). If I try to calculate 15^14 then I get "29192926025390624". But if I calculate it with Wolfram Alpha I get "29192926025390625". As you can see this only difference is 1 number. Wolfram Alpha is correct though. Why isn't C# ? and how do I fix this so I can get the correct value in C# ?7

My code is fairly simple since I'm just trying with hardcoded examples. So what I'm doing is : Math.Pow(15,14); This gives 29192926025390624. And not "29192926025390625" which is the correct answer.

Links : Wolfram Alpha

Answer

Heinzi picture Heinzi · Nov 28, 2010

Math.Pow operates on floating-point types, which are by definition inaccurate. If you need arbitrary precision integers, use an arbitrary precision integer type such as the BigInteger structure. BigInteger also has a Pow method.

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