Negative base numbers: Difference between revisions

=={{header|C#|C sharp}}==

{{trans|Java}}

<lang csharp>using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace NegativeBaseNumbers {

class Program {

const string DIGITS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

static string EncodeNegativeBase(long n, int b) {

if (b < -62 || b > -1) {

throw new ArgumentOutOfRangeException("b");

}

if (n == 0) {

return "0";

}

StringBuilder output = new StringBuilder();

long nn = n;

while (nn != 0) {

int rem = (int)(nn % b);

nn /= b;

if (rem < 0) {

nn++;

rem -= b;

}

output.Append(DIGITS[rem]);

}

return new string(output.ToString().Reverse().ToArray());

}

static long DecodeNegativeBase(string ns, int b) {

if (b < -62 || b > -1) {

throw new ArgumentOutOfRangeException("b");

}

if (ns == "0") {

return 0;

}

long total = 0;

long bb = 1;

for (int i = ns.Length - 1; i >= 0; i--) {

char c = ns[i];

total += DIGITS.IndexOf(c) * bb;

bb *= b;

}

return total;

}

static void Main(string[] args) {

List<Tuple<long, int>> nbl = new List<Tuple<long, int>>() {

new Tuple<long, int>(10,-2),

new Tuple<long, int>(146,-3),

new Tuple<long, int>(15,-10),

new Tuple<long, int>(-34025238427,-62),

};

foreach (var p in nbl) {

string ns = EncodeNegativeBase(p.Item1, p.Item2);

Console.WriteLine("{0,12} encoded in base {1,-3} = {2}", p.Item1, p.Item2, ns);

long n = DecodeNegativeBase(ns, p.Item2);

Console.WriteLine("{0,12} decoded in base {1,-3} = {2}", ns, p.Item2, n);

Console.WriteLine();

}

}

}

}</lang>

{{out}}

<pre> 10 encoded in base -2 = 11110

11110 decoded in base -2 = 10

146 encoded in base -3 = 21102

21102 decoded in base -3 = 146

15 encoded in base -10 = 195

195 decoded in base -10 = 15

-34025238427 encoded in base -62 = csharp

csharp decoded in base -62 = -34025238427</pre>