Convert vbscript function to C#

I need to convert the following vb script function to C# to be used in a new application.
Function EX(ByRef x, p, m)
    y = 1
    Do While p > 0
        Do While (p / 2) = Int((p / 2))
            x = (x * x) - (Int((x * x) / m) * m)
            p = p / 2
        Loop
        y = (x * y) - (Int((x * y) / m) * m)
        p = p - 1
    Loop
    EX = y
End Function

Open in new window


This is my attempt, but it does not work correctly. The original returns y as a number less than 1000 and my conversion returns numbers in the millions and runs many more iterations of the inner loop.

       public int Ex(ref int x, int p, int m)
        {
            y = 1;
            do
            {
                do
                {
                    x = (x * x) - (((x * x) / m) * m);
                    p = p / 2;
                }
                while ((p % 2) == 0);
                y = (x * y) - (((x * y) / m) * m);
                p = p - 1;
            }
            while (p > 0);
            return y;
        }

Open in new window


I have attached another version of the vbscript function with logging statements and the logs it generated so you can see the data involved since they used no datatypes when it was written.

Function EX(ByRef x, p, m)
	logmessage "gis.asp: EX", "	Variables passed in: x = " & x & " p = " & p & " m = " & m
    y = 1
    i =1
    o =1
    Do While p > 0
        Do While (p / 2) = Int((p / 2))
            x = (x * x) - (Int((x * x) / m) * m)
            logmessage "gis.asp: EX", "		(x * x)" & (x * x) & " - (Int((x * x) / m)" & Int((x * x) / m) & " * m)" & (Int((x * x) / m) * m) & " = " & (x * x) - (Int((x * x) / m) * m)
            p = p / 2
            logmessage "gis.asp: EX", "		inner iteration"& i &": p/2 = " & p/2 & " p = " & p & " y = " & y & " x = " & x
            i = i + 1
        Loop
			logmessage "gis.asp: EX", "	post inner do: p = " & p & " y = " & y & " x = " & x
			i=1
        y = (x * y) - (Int((x * y) / m) * m)
        p = p - 1
            logmessage "gis.asp: EX", "	outer iteration"& o &": p = " & p & " y = " & y & " x = " & x
            o = o + 1
    Loop
    o=1
        logmessage "gis.asp: EX", "post outer do: p = " & p & " y = " & y & " x = " & x
    EX = y
End Function


3/30/2012 9:26:46 AM	gis.asp: EX		Variables passed in: x = 15344606 p = 18346651 m = 22833299
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 18346651 y = 1 x = 15344606
3/30/2012 9:26:46 AM	gis.asp: EX		outer iteration1: p = 18346650 y = 15344606 x = 15344606
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)506571035879689 - (Int((x * x) / m)22185626 * m)506571031960174 = 3919515
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration1: p/2 = 4586662.5 p = 9173325 y = 15344606 x = 22507133
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 9173325 y = 15344606 x = 22507133
3/30/2012 9:26:46 AM	gis.asp: EX		outer iteration2: p = 9173324 y = 10547111 x = 22507133
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)15362597835225 - (Int((x * x) / m)672815 * m)15362586066685 = 11768540
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration1: p/2 = 2293331 p = 4586662 y = 10547111 x = 3919515
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)138498533731600 - (Int((x * x) / m)6065638 * m)138498526079762 = 7651838
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration2: p/2 = 1146665.5 p = 2293331 y = 10547111 x = 11768540
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 2293331 y = 10547111 x = 11768540
3/30/2012 9:26:46 AM	gis.asp: EX		outer iteration3: p = 2293330 y = 994040 x = 11768540
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)58550624778244 - (Int((x * x) / m)2564264 * m)58550606626936 = 18151308
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration1: p/2 = 573332.5 p = 1146665 y = 994040 x = 7651838
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 1146665 y = 994040 x = 7651838
3/30/2012 9:26:46 AM	gis.asp: EX		outer iteration4: p = 1146664 y = 4482640 x = 7651838
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)329469982110864 - (Int((x * x) / m)14429363 * m)329469959758537 = 22352327
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration1: p/2 = 286666 p = 573332 y = 4482640 x = 18151308
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)499626522314929 - (Int((x * x) / m)21881486 * m)499626512402314 = 9912615
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration2: p/2 = 143333 p = 286666 y = 4482640 x = 22352327
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)98259936138225 - (Int((x * x) / m)4303361 * m)98259928417939 = 7720286
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration3: p/2 = 71666.5 p = 143333 y = 4482640 x = 9912615
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 143333 y = 4482640 x = 9912615
3/30/2012 9:26:46 AM	gis.asp: EX		outer iteration5: p = 143332 y = 11484547 x = 9912615
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)59602815921796 - (Int((x * x) / m)2610346 * m)59602810711454 = 5210342
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration1: p/2 = 35833 p = 71666 y = 11484547 x = 7720286
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)27147663756964 - (Int((x * x) / m)1188950 * m)27147650846050 = 12910914
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration2: p/2 = 17916.5 p = 35833 y = 11484547 x = 5210342
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 35833 y = 11484547 x = 5210342
3/30/2012 9:26:46 AM	gis.asp: EX		outer iteration6: p = 35832 y = 12894538 x = 5210342
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)166691700315396 - (Int((x * x) / m)7300377 * m)166691690853723 = 9461673
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration1: p/2 = 8958 p = 17916 y = 12894538 x = 12910914
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)89523255958929 - (Int((x * x) / m)3920732 * m)89523246054868 = 9904061
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration2: p/2 = 4479 p = 8958 y = 12894538 x = 9461673
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)98090424291721 - (Int((x * x) / m)4295937 * m)98090414006163 = 10285558
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration3: p/2 = 2239.5 p = 4479 y = 12894538 x = 9904061
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 4479 y = 12894538 x = 9904061
3/30/2012 9:26:46 AM	gis.asp: EX		outer iteration7: p = 4478 y = 5614290 x = 9904061
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)105792703371364 - (Int((x * x) / m)4633264 * m)105792702257936 = 1113428
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration1: p/2 = 1119.5 p = 2239 y = 5614290 x = 10285558
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 2239 y = 5614290 x = 10285558
3/30/2012 9:26:46 AM	gis.asp: EX		outer iteration8: p = 2238 y = 7253850 x = 10285558
3/30/2012 9:26:46 AM	gis.asp: EX			(x * x)1239721911184 - (Int((x * x) / m)54294 * m)1239711135906 = 10775278
3/30/2012 9:26:46 AM	gis.asp: EX			inner iteration1: p/2 = 559.5 p = 1119 y = 7253850 x = 1113428
3/30/2012 9:26:46 AM	gis.asp: EX		post inner do: p = 1119 y = 7253850 x = 1113428
3/30/2012 9:26:47 AM	gis.asp: EX		outer iteration9: p = 1118 y = 22342221 x = 1113428
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)116106615977284 - (Int((x * x) / m)5084968 * m)116106594749432 = 21227852
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration1: p/2 = 279.5 p = 559 y = 22342221 x = 10775278
3/30/2012 9:26:47 AM	gis.asp: EX		post inner do: p = 559 y = 22342221 x = 10775278
3/30/2012 9:26:47 AM	gis.asp: EX		outer iteration10: p = 558 y = 907071 x = 10775278
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)450621700533904 - (Int((x * x) / m)19735286 * m)450621686088514 = 14445390
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration1: p/2 = 139.5 p = 279 y = 907071 x = 21227852
3/30/2012 9:26:47 AM	gis.asp: EX		post inner do: p = 279 y = 907071 x = 21227852
3/30/2012 9:26:47 AM	gis.asp: EX		outer iteration11: p = 278 y = 7727885 x = 21227852
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)208669292252100 - (Int((x * x) / m)9138814 * m)208669272567386 = 19684714
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration1: p/2 = 69.5 p = 139 y = 7727885 x = 14445390
3/30/2012 9:26:47 AM	gis.asp: EX		post inner do: p = 139 y = 7727885 x = 14445390
3/30/2012 9:26:47 AM	gis.asp: EX		outer iteration12: p = 138 y = 17056263 x = 14445390
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)387487965261796 - (Int((x * x) / m)16970301 * m)387487956852999 = 8408797
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration1: p/2 = 34.5 p = 69 y = 17056263 x = 19684714
3/30/2012 9:26:47 AM	gis.asp: EX		post inner do: p = 69 y = 17056263 x = 19684714
3/30/2012 9:26:47 AM	gis.asp: EX		outer iteration13: p = 68 y = 3411381 x = 19684714
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)70707866987209 - (Int((x * x) / m)3096699 * m)70707854180001 = 12807208
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration1: p/2 = 17 p = 34 y = 3411381 x = 8408797
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)164024576755264 - (Int((x * x) / m)7183568 * m)164024556030832 = 20724432
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration2: p/2 = 8.5 p = 17 y = 3411381 x = 12807208
3/30/2012 9:26:47 AM	gis.asp: EX		post inner do: p = 17 y = 3411381 x = 12807208
3/30/2012 9:26:47 AM	gis.asp: EX		outer iteration14: p = 16 y = 4229193 x = 12807208
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)429502081722624 - (Int((x * x) / m)18810338 * m)429502071845062 = 9877562
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration1: p/2 = 4 p = 8 y = 4229193 x = 20724432
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)97566231063844 - (Int((x * x) / m)4272980 * m)97566229961020 = 1102824
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration2: p/2 = 2 p = 4 y = 4229193 x = 9877562
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)1216220774976 - (Int((x * x) / m)53265 * m)1216215671235 = 5103741
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration3: p/2 = 1 p = 2 y = 4229193 x = 1102824
3/30/2012 9:26:47 AM	gis.asp: EX			(x * x)26048172195081 - (Int((x * x) / m)1140797 * m)26048158999303 = 13195778
3/30/2012 9:26:47 AM	gis.asp: EX			inner iteration4: p/2 = 0.5 p = 1 y = 4229193 x = 5103741
3/30/2012 9:26:47 AM	gis.asp: EX		post inner do: p = 1 y = 4229193 x = 5103741
3/30/2012 9:26:47 AM	gis.asp: EX		outer iteration15: p = 0 y = 230 x = 5103741
3/30/2012 9:26:47 AM	gis.asp: EX	post outer do: p = 0 y = 230 x = 5103741

Open in new window

dgerlerAsked:
Who is Participating?
 
dgerlerConnect With a Mentor Author Commented:
It's fixed.

here's the functioning code..

x*x was overflowing the the int32 datatype and causing the number to go negative.

        public int Ex(ref Int64 x, Int64 p, Int64 m)
        {
            Int64 y = 1;
            while (p > 0)
            {
                while ((p % 2) == 0)
                {
                    x = (x * x) - (Convert.ToInt64((x * x) / m) * m);
                    p = p / 2;
                }
                y = (x * y) - (Convert.ToInt64((x * y) / m) * m);
                p = p - 1;
            }
            return (int)y;
        }

Open in new window

0
 
sammySeltzerConnect With a Mentor Commented:
public object EX(ref System.Object x, System.Object p, System.Object m)
{
	y = 1;
	while (p > 0) {
		while ((p / 2) == Conversion.Int((p / 2))) {
			x = (x * x) - (Conversion.Int((x * x) / m) * m);
			p = p / 2;
		}
		y = (x * y) - (Conversion.Int((x * y) / m) * m);
		p = p - 1;
	}
	return y;
}

Open in new window


http://converter.telerik.com/
0
 
dgerlerAuthor Commented:
That doesn't compile. Math can't be performed on the objects.

I have modified it to:

        public int Ex(ref int x, int p, int m)
        {
            int y = 1;
            while (p > 0)
            {
                while ((p / 2) == Convert.ToInt32(p/2))
                {
                    x = (x * x) - (Convert.ToInt32((x * x) / m) * m);
                    p = p / 2;
                }
                y = (x * y) - (Convert.ToInt32((x * y) / m) * m);
                p = p - 1;
            }
            return y;
        }

Open in new window


It still doesn't work correctly.
0
 
dgerlerAuthor Commented:
While SammySelzer provided some code it was not complete and require much more work to fix it. The main thing I got from it was changing the do..while to a while
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.