Decimal to Binary and vice versa

Giwa Abdulhakeem

15y9.2k.NET

Good day,

I want to convert decimal to binary number using c# asp.net. I know there is a certain 'CONVERT' method i could to achieve this, but is that i want the result with details.

For example: decimal to binary (10 to base2)
10 / 2 = 5 R 0
5 / 2 = 2 R 1
2 / 2 = 1 R 0
1 / 2 = 0 R 1

So the corresponding result to 10 = 1010 in base 2. So therefore, if a user type in 10 he gets 1010 and how the result was came about. please help ... :) .. Thanks in advance.

11 Replies

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Vulpes15y ago
Accepted answer
Giwa,

As requested in your e-mail, I've extended the program to cover the 4 additional conversions.

Your RadioButtonList1 should now have the following 6 options:

1. Binary to Decimal
2. Decimal to Binary
3. Hex to Decimal
4. Decimal to Hex
5. Hex to Binary
6. Binary to Hex

The last 2 don't do much as you can convert between the two just by replacing 4 binary digits with the corresponding hex digit or vice versa - no calculations are necessary.

I've altered all the routines to use 'long' rather than 'int' arithmetic so that bigger numbers can be catered for. However, there's no overflow checking so don't make them too big!

public partial class _Default : System.Web.UI.Page
{
   protected void Page_Load(object sender, EventArgs e)
   {

   }

   public bool BinToDec(string bin)
   {
   if (String.IsNullOrEmpty(bin))
   {
   Label1.Text = "Binary number must contain at least one digit";
   return false;
   }

   long total = 0;
   long pow2 = 1;
   string text = "";

   for (int i = bin.Length - 1; i >= 0; i--)
   {
   char digit = bin[i];
   if (digit != '0' && digit != '1')
   {
   Label1.Text = "Binary number can only contain 0 or 1";
   return false;
   }

   long product = (digit - 48) * pow2;
   total += product;
   text += String.Format("{0} x {1} = {2} T {3}\r\n", digit, pow2, product, total);
   pow2 *= 2;
   }

   text += String.Format("\r\n{0} in decimal is {1}", bin, total);
   TextBox2.Text = text;
   return true;
   }

   public bool DecToBin(long dec)
   {
   if (dec < 0)
   {
   Label1.Text = "Can't be negative";
   return false;
   }

   long original = dec;
   List list = new List();
   string text = "";

   do
   {
   long div = dec / 2;
   long rem = dec % 2;
   text += String.Format("{0} / 2 = {1} R {2}\r\n", dec, div, rem);
   dec = div;
   list.Add((char)(rem + 48));
   }
   while (dec > 0);

   list.Reverse();
   string bin = new string(list.ToArray());

   text += String.Format("\r\n{0} in binary is {1}", original, bin);
   TextBox2.Text = text;
   return true;
   }

   public bool HexToDec(string hex)
   {
   if (String.IsNullOrEmpty(hex))
   {
   Label1.Text = "Hexadecimal number must contain at least one digit";
   return false;
   }

   hex = hex.ToUpper();
   string digits = "0123456789ABCDEF";
   long total = 0;
   long pow16 = 1;
   string text = "";

   for (int i = hex.Length - 1; i >= 0; i--)
   {
   char digit = hex[i];
   if (digits.IndexOf(digit) == -1)
   {
   Label1.Text = "Hexadecimal number can only contain 0 - 9 or A - F";
   return false;
   }

   long product = ((digit <= '9') ? (digit - 48) : (digit - 55)) * pow16;
   total += product;
   text += String.Format("{0} x {1} = {2} T {3}\r\n", digit, pow16, product, total);
   pow16 *= 16;
   }

   text += String.Format("\r\n0x{0} in decimal is {1}", hex, total);
   TextBox2.Text = text;
   return true;
   }

   public bool DecToHex(long dec)
   {
   if (dec < 0)
   {
   Label1.Text = "Can't be negative";
   return false;
   }

   string digits = "0123456789ABCDEF";
   long original = dec;
   List list = new List();
   string text = "";

   do
   {
   long div = dec / 16;
   long rem = dec % 16;
   string extra = "";
   if (rem > 9) extra = "(" + digits[(int)rem] + ")";
   text += String.Format("{0} / 16 = {1} R {2}{3}\r\n", dec, div, rem, extra);
   dec = div;
   list.Add(digits[(int)rem]);
   }
   while (dec > 0);

   list.Reverse();
   string hex = new string(list.ToArray());

   text += String.Format("\r\n{0} in hexadecimal is 0x{1}", original, hex);
   TextBox2.Text = text;
   return true;
   }

   public bool HexToBin(string hex)
   {
   if (String.IsNullOrEmpty(hex))
   {
   Label1.Text = "Hexadecimal number must contain at least one digit";
   return false;
   }

   hex = hex.ToUpper();
   string digits = "0123456789ABCDEF";
   System.Text.StringBuilder sb = new System.Text.StringBuilder();

   for (int i = 0; i < hex.Length; i++)
   {
   char digit = hex[i];

   if (digits.IndexOf(digit) == -1)
   {
   Label1.Text = "Hexadecimal number can only contain 0 - 9 or A - F";
   return false;
   }

   int number = (digit <= '9') ? (digit - 48) : (digit - 55);
   string nybble = Convert.ToString(number, 2).PadLeft(4, '0');
   sb.Append(nybble);
   }

   string bin = sb.ToString();
   string text = "";

   for (int i = hex.Length - 1; i >= 0; i--)
   {
   string nybble = bin.Substring(4 * i, 4);
   text += String.Format("{0} = {1}\r\n", hex[i], nybble);
   }

   text += String.Format("\r\n0x{0} in binary is {1}", hex, bin);
   TextBox2.Text = text;
   return true;
   }

   public bool BinToHex(string bin)
   {
   if (String.IsNullOrEmpty(bin))
   {
   Label1.Text = "Binary number must contain at least one digit";
   return false;
   }

   for (int i = 0; i < bin.Length; i++)
   {
   char digit = bin[i];
   if (digit != '0' && digit != '1')
   {
   Label1.Text = "Binary number can only contain 0 or 1";
   return false;
   }
   }

   string original = bin;

   int div = bin.Length / 4;
   int rem = bin.Length % 4;

   if (rem > 0)
   {
   div++;
   bin = bin.PadLeft(4 * div, '0');
   }

   List list = new List();
   string text = "";

   for (int i = bin.Length - 4; i >= 0; i -= 4)
   {
   string nybble = bin.Substring(i, 4);
   char digit = Convert.ToInt32(nybble, 2).ToString("X")[0];
   text += String.Format("{0} = {1}\r\n", nybble, digit);
   list.Add(digit);
   }

   list.Reverse();
   string hex = new string(list.ToArray());
   text += String.Format("\r\n{0} in hexadecimal is 0x{1}", original, hex);
   TextBox2.Text = text;
   return true;
   }

   protected void Button1_Click(object sender, EventArgs e)
   {
   Label1.Text = "";
   TextBox2.Text = "";

   string number = TextBox1.Text;

   if (number.Length == 0)
   {
   Label1.Text = "Please enter the number to be converted";
   return;
   }

   switch (RadioButtonList1.SelectedIndex) // binary to decimal
   {
   case 0: // binary to decimal
   if (!BinToDec(number)) return;
   break;

   case 1: // decimal to binary
   long arg;
   if (!long.TryParse(number, out arg))
   {
   Label1.Text = "Not a valid decimal number";
   return;
   }
   if (!DecToBin(arg)) return;
   break;

   case 2: // hexadecimal to decimal
   if (!HexToDec(number)) return;
   break;

   case 3: // decimal to hexadecimal
   long arg2;
   if (!long.TryParse(number, out arg2))
   {
   Label1.Text = "Not a valid decimal number";
   return;
   }
   if (!DecToHex(arg2)) return;
   break;

   case 4: // hexadecimal to binary
   if (!HexToBin(number)) return;
   break;

   case 5: // binary to hexadecimal
   if (!BinToHex(number)) return;
   break;

   default : // no radiobutton selected
   Label1.Text = "The conversion type has not been selected";
   return;
   }

   TextBox1.Text = "";
   }
}
Giwa Abdulhakeem15y ago
Really appreciate your effort. Thanks Brother.
Giwa Abdulhakeem15y ago
A really good one I must say. Kudos to him.
Suthish Nair15y ago
Vulpes, you are a good teacher :)
Vulpes15y ago
Suppose you have the following controls on your web page:

1. A single line textbox, TextBox1, for the user to enter the number to be converted.

2. A multi-line textbox, TextBox2, to display the results.

3. A label, Label1, to display any error messages.

4. A RadioButtonList, radiButtonList, with 2 buttons to select the conversion type : Binary to Decimal (first button) or Decimal to Binary (second button).

5. A button, Button1, for the user to press to start the conversion.

If you add a Click handler for the button plus the following code to your 'code behind' file for the page, then it should work - notice, though, that I've had to change the methods a bit:

public partial class _Default : System.Web.UI.Page
{
   protected void Page_Load(object sender, EventArgs e)
   {

   }

   public bool DecToBin (int dec)
   {
   if (dec < 0)
   {
   Label1.Text = "Can't be negative";
   return false;
   }

   int original = dec;

   List list = new List();
   string text = "";

   do
   {
   int div = dec / 2;
   int rem = dec % 2;
   text += String.Format("{0} / 2 = {1} R {2}\r\n", dec, div, rem);
   dec = div;
   list.Add((char)(rem + 48));
   }
   while(dec > 0);

   list.Reverse();
   string bin = new string(list.ToArray());

   text += String.Format("\r\n{0} in binary is {1}", original, bin);
   TextBox2.Text = text;
   return true;
   }

   public bool BinToDec (string bin)
   {
   if (String.IsNullOrEmpty(bin))
   {
   Label1.Text = "Binary number must contain at least one digit";
   return false;
   }

   int total = 0;
   int pow2 = 1;
   string text = "";

   for (int i = bin.Length - 1; i >= 0; i--)
   {
   char digit = bin[i];
   if (digit != '0' && digit != '1')
   {
   Label1.Text = "Binary number can only contain 0 or 1";
   return false;
   }

   int product = (digit - 48) * pow2;
   total += product;
   text += String.Format("{0} x {1} = {2} T {3}\r\n", digit, pow2, product, total);
   pow2 *= 2;
   }

   text += String.Format("\r\n{0} in decimal is {1}", bin, total);
   TextBox2.Text = text;
   return true;
   }

   protected void Button1_Click(object sender, EventArgs e)
   {
   Label1.Text = "";
   TextBox2.Text = "";

   string number = TextBox1.Text;

   if (number.Length == 0)
   {
   Label1.Text = "Please enter the number to be converted";
   return;
   }

   switch (RadioButtonList1.SelectedIndex) // binary to decimal
   {
   case 0: // binary to decimal
   if (!BinToDec(number)) return;
   break;

   case 1: // decimal to binary
   int arg;
   if(!int.TryParse(number, out arg))
   {
   Label1.Text = "Not a valid decimal number";
   return;
   }
   if (!DecToBin(arg)) return;
   break;
   default : // no radiobutton selected
   Label1.Text = "The conversion type has not been selected";
   return;
   }

   TextBox1.Text = "";
   }
}
Giwa Abdulhakeem15y ago
I would love to know how to do this on a web page in asp.net c#.
Crish15y ago
good example solution for custom decimal to binary number using c# asp.net.
Vulpes15y ago
With regard to the binary to decimal conversion, I'm not sure what format you want the intermediate steps to be in, so I've just done what I think:

using System;

class Test
{
static void Main()
{
string bin = "1010";
int dec = BinToDec(bin);
Console.WriteLine("{0} in decimal is {1}", bin, dec);
Console.ReadKey();
}

static int BinToDec (string bin)
{
if (String.IsNullOrEmpty(bin))
throw new ArgumentException("Binary number must contain at least one digit");
int total = 0;
int pow2 = 1;

for (int i = bin.Length - 1; i >= 0; i--)
{
char digit = bin[i];
if (digit != '0' && digit != '1')
throw new ArgumentException("Binary number can only contain 0 or 1");

int product = (digit - 48) * pow2;
total += product;
Console.WriteLine("{0} x {1} = {2} T {3}", digit, pow2, product, total);
pow2 *= 2;
}

return total;
}
}
Vulpes15y ago
This should do the decimal to binary conversion in the form you want it:

using System;
using System.Collections.Generic;

class Test
{
   static void Main()
   {
   int dec = 10;
   string bin = DecToBin(dec);
   Console.WriteLine("{0} in binary is {1}", dec, bin);
   Console.ReadKey();
   }

   static string DecToBin (int dec)
   {
   if (dec < 0) return ""; // can't be negative
   List list = new List();

   do
   {
   int div = dec / 2;
   int rem = dec % 2;
   Console.WriteLine("{0} / 2 = {1} R {2}", dec, div, rem);
   dec = div;
   list.Add((char)(rem + 48));
   }
   while(dec > 0);

   list.Reverse();
   return new string(list.ToArray());
   }
}
Giwa Abdulhakeem15y ago
Hi,
Thanks for the quick response really appreciate it. From the link you posted i tried the section which say Decimal to Binary and i get this error 'Index was outside the bounds of the array.' Tried debugging but all to no result. Would really appreciate any help. Cheers
Mahesh Chand15y ago
Check this post:

http://www.csharphelp.com/2007/09/converting-between-binary-and-decimal-in-c/