Computing only the N-th Digit of Pi

[Juggler_IN]

I need help in fixing a C to VBA conversion code.

The code outputs the specified n-th digit of pi in base-10 (Decimal System) on the lines of the Bailey–Borwein–Plouffe formula which outputs the specified n-th digit of pi in base-16 (Hexadecimal System).

The converted, but not functional, VBA code and the reference C code are enclosed.

A fully-functional execution of the C code can be viewed at tio.run which is an online C compiler.

Sub Main0()
' Expected output for i = 1 to 50 is 1 4 1 5 9 2 6 5 3 5 8 9 7 9 3 2 3 8 4 6 2 6 4 3 3 8 3 2 7 9 4 0 2 8 8 4 1 9 7 1 6 9 3 9 9 3 7 5 1 0 5.

    For i = 0 To 50
        Debug.Print NthPi(i) & " ";
    Next i

End Sub
Function NthPi(ByVal d As Integer) As Long

    Dim ll, j, i

    ll = Int((d + 2) * 10 / 3 + 2)
    j = 0
    i = 0

    Dim x, r

    ReDim x(0 To ll)
    ReDim r(0 To ll)

    Do
        x(j) = 20
        j = j + 1
    Loop While j < ll

    Dim c, n, e, p

    p = 0

    Do While i < d

        j = 0
        c = 0

        Do
            n = ll - j - 1
            e = n * 2 + 1
            r(j) = (x(j) + c) Mod e
            c = (x(j) / e) * n
            j = j + 1
        Loop While j < ll

        ll = ll - 1
        p = x(ll) / 10
        r(ll) = x(ll + 1) Mod 10

        j = 0
        
        Do
            x(j) = r(j) * 10
            j = j + 1
        Loop While j < ll

        i = i + 1

    Loop

    NthPi = p Mod 10

End Function

namespace System.Linq
{
    class P
    {
        static void Main()
        {
            for (int i = 0; i <= 50; ++i)
            {
                Console.Write(NthPi(i));
            }

            Console.WriteLine();
            Console.ReadLine();
        }

        static long NthPi(int d)
        {
            int l = (d+=2) * 10 / 3 + 2, j = 0, i = 0;

            long[] x = new long[l], r = new long[l];

            for (; j < l;)
                x[j++] = 20;

            long c, n, e, p = 0;

            for (; i < d; ++i)
            {
                for (j = 0, c = 0; j < l; c = (x[j++] / e) * n)
                {
                    n = l - j - 1;
                    e = n * 2 + 1;
                    
                    r[j] = (x[j] += c) % e;
                }
                
                p = x[--l] / 10;
                
                r[l] = x[l++] % 10;

                for (j = 0; j < l;)
                    x[j] = r[j++] * 10;
            }
            
            return p % 10;
        }
    }
}

Cross-posted at: ExcelForum.com
An alternate code (which I don't want to pursue) cross-posted at: MrExcel.com

 

[Fluff]

Duplicate to: Nth digit of Pi

In future, please do not post the same question multiple times. Per Forum Rules (#12), posts of a duplicate nature will be locked or deleted.

In relation to your question here, I have closed this thread so please continue in the linked thread.