select the right type of variable C#

Question

i want to create pi more than 16 thousand numbers after the decimal point but the problam is that i kant find any type that could fill my wishes. I tried to use object but it rounds the number after 10 I thought using string but string type wont be able to do minus or plus and if i will convert to int it will become round. do you know any other types i can use or how can i make it work with a string for example http://files.extremeoverclocking.com/file.php?f=36 this program is able to calculate up to 32 million

thnx

Answer 1

Take a look at this page and it's BigNumber class.

The first thing to note is that we can't use any of the primitive types in C#: they just don't have enough precision (the double type, for example, only has 15 significant digits, and we want to calculate, say, 10000). We need a large precision number library, but there's nothing like that in the .NET Framework, and so the first thing we'll have to do is write a BigNumber class.

That page also provides an example usage for calculating pi out to 1000 decimal places, so it should be fairly trivial to run it for 16000.

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Running it for 16000 digits takes me about a second and a half, for 160,000 digits takes me a bit over 2 minutes.

Here's my PrintAsTable() function, which the linked post leaves as an exercise for the reader:

public string PrintAsTable() {
    var data = Print();
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < data.Length; i++)
    {
        if (data[i] == '.') sb.AppendLine(".");
        else if ((i -1) % 50 == 0) sb.AppendLine(data[i].ToString());
        else if ((i -1) % 10 == 0) {sb.Append(data[i].ToString()); sb.Append(" ");}
        else sb.Append(data[i].ToString());
    }
    return sb.ToString();
}