Convert integer to binary in C#

Question

How to convert an integer number into its binary representation?

I'm using this code:

String input = "8";
String output = Convert.ToInt32(input, 2).ToString();

But it throws an exception:

Could not find any parsable digits

Are you trying to convert the string representation of a number, or an actual number? And are you trying to convert to decimal, or int? Your example doesn't really match your question. — womp, Jun 02 '10 at 04:18
If you're looking to convert decimal to bytes, you can use this code: https://gist.github.com/eranbetzalel/5384006#file-decimalbytesconvertor-cs — Eran Betzalel, Apr 14 '13 at 20:14
You're trying to parse a base-10 string as base-2. That's why the call fails. — R.J. Dunnill, Jul 22 '19 at 17:08

score 535 · Accepted Answer · answered Jun 02 '10 at 04:24

535

Your example has an integer expressed as a string. Let's say your integer was actually an integer, and you want to take the integer and convert it to a binary string.

int value = 8;
string binary = Convert.ToString(value, 2);

Which returns 1000.

answered Jun 02 '10 at 04:24

Anthony Pegram

123,721
27
225
246

1

is there any similar method to convert binary to decimal? – kashif Jan 24 '13 at 08:26
52

@kashif `int value = Convert.ToInt32("1101", 2)` would give `value` the value 13. – flindeberg Mar 05 '13 at 18:20
How does this work? is the "2" the base and will work for any base? – Xonatron May 22 '21 at 19:25
2

@Xonatron: https://learn.microsoft.com/en-us/dotnet/api/system.convert.tostring?view=net-5.0#System_Convert_ToString_System_Int32_System_Int32_ – Anthony Pegram May 23 '21 at 04:10

sritmak · Answer 2 · 2021-08-30T14:29:54.037

60

Convert from any classic base to any base in C#

string number = "100";
int fromBase = 16;
int toBase = 10;

string result = Convert.ToString(Convert.ToInt32(number, fromBase), toBase);

// result == "256"

Supported bases are 2, 8, 10 and 16

edited Aug 30 '21 at 14:29

answered Dec 18 '12 at 23:08

sritmak

989
9
18

1

This will not work. I simply tried `string binary = Convert.ToString(533, 26);` and got a ArgumentException: Invalid base – Magnum Apr 25 '14 at 18:09
8

Yep, from MSDN: only classic bases are supported http://msdn.microsoft.com/en-us/library/8s62fh68(v=vs.110).aspx toBase Type: System.Int32 The base of the return value, which must be 2, 8, 10, or 16. – sritmak Apr 30 '14 at 08:12

score 41 · Answer 3 · edited Jan 14 '12 at 13:49

41

Very Simple with no extra code, just input, conversion and output.

using System;

namespace _01.Decimal_to_Binary
{
    class DecimalToBinary
    {
        static void Main(string[] args)
        {
            Console.Write("Decimal: ");
            int decimalNumber = int.Parse(Console.ReadLine());

            int remainder;
            string result = string.Empty;
            while (decimalNumber > 0)
            {
                remainder = decimalNumber % 2;
                decimalNumber /= 2;
                result = remainder.ToString() + result;
            }
            Console.WriteLine("Binary:  {0}",result);
        }
    }
}

edited Jan 14 '12 at 13:49

Mark Hall

53,938
9
94
111

answered Jan 14 '12 at 13:47

Xenon

419
4
2

1

For a generic alphabet, this should be do{ [...] }while(decimalNumber > 0); – Stefan Steiger Mar 04 '15 at 15:51
In case of decimalNumber = 0, result is Empty. Please update to while (decimalNumber > 0 || string.IsNullOrEmpty(result)) – akkapolk Sep 23 '19 at 07:30

score 15 · Answer 4 · edited Oct 24 '11 at 15:36

15

http://zamirsblog.blogspot.com/2011/10/convert-decimal-to-binary-in-c.html

    public string DecimalToBinary(string data)
    {
        string result = string.Empty;
        int rem = 0;
        try
        {
            if (!IsNumeric(data))
                error = "Invalid Value - This is not a numeric value";
            else
            {
                int num = int.Parse(data);
                while (num > 0)
                {
                    rem = num % 2;
                    num = num / 2;
                    result = rem.ToString() + result;
                }
            }
        }
        catch (Exception ex)
        {
            error = ex.Message;
        }
        return result;
    }

edited Oct 24 '11 at 15:36

wRAR

25,009
4
84
97

answered Oct 24 '11 at 09:10

Zamir

167
1
2

2

Not sure how this differs from Xenon's answer. – Joshua Drake Nov 08 '12 at 17:22
6

He answered this before Xenon – Reza Taibur May 28 '16 at 19:06

score 12 · Answer 5 · answered Jan 07 '16 at 21:32

12

primitive way:

public string ToBinary(int n)
{
    if (n < 2) return n.ToString();

    var divisor = n / 2;
    var remainder = n % 2;

    return ToBinary(divisor) + remainder;
}

answered Jan 07 '16 at 21:32

Daniel B

3,109
2
33
42

3

Fails with negatives, but I upvoted anyway because it's a fun answer. – BrainSlugs83 Aug 09 '20 at 10:36
appreciated yr feedback @BrainSlugs83 – Daniel B Aug 09 '20 at 19:13

Sanan Fataliyev · Answer 6 · 2021-05-20T00:18:37.743

9

Another alternative but also inline solution using Enumerable and LINQ is:

int number = 25;
    
string binary = Enumerable.Range(0, (int)Math.Log(number, 2) + 1).Aggregate(string.Empty, (collected, bitshifts) => ((number >> bitshifts) & 1 ) + collected);

edited May 20 '21 at 00:18

answered May 10 '18 at 11:55

Sanan Fataliyev

612
8
16

1

After trying many (but not all) of the non-BCL answers here, this is the first answer I found that actually works. Most of them fail spectacularly. – InteXX Sep 20 '19 at 14:34
1

thank you for discovering my code :) but as you see, it's joke from performance point of view – Sanan Fataliyev Sep 21 '19 at 19:28
Well, we can't have everything, can we? ;-) – InteXX Sep 21 '19 at 23:50
1

This answer legit made me laugh. Here have an up vote, you deserve it. – BrainSlugs83 Aug 09 '20 at 10:33

score 8 · Answer 7 · answered Jun 02 '10 at 04:21

Convert.ToInt32(string, base) does not do base conversion into your base. It assumes that the string contains a valid number in the indicated base, and converts to base 10.

So you're getting an error because "8" is not a valid digit in base 2.

String str = "1111";
String Ans = Convert.ToInt32(str, 2).ToString();

Will show 15 (1111 base 2 = 15 base 10)

String str = "f000";
String Ans = Convert.ToInt32(str, 16).ToString();

Will show 61440.

score 6 · Answer 8 · answered Mar 19 '19 at 21:34

6

    static void convertToBinary(int n)
    {
        Stack<int> stack = new Stack<int>();
        stack.Push(n);
        // step 1 : Push the element on the stack
        while (n > 1)
        {
            n = n / 2;
            stack.Push(n);
        }

        // step 2 : Pop the element and print the value
        foreach(var val in stack)
        {
            Console.Write(val % 2);
        }
     }

answered Mar 19 '19 at 21:34

rahul sharma

61
2
3

1

Hello ! You should add some comments with the code you posted :) – toshiro92 Mar 19 '19 at 21:40
1

This function will convert integer to binary in C#. To convert integer to Binary, we repeatedly divide the quotient by the base, until the quotient is zero, making note of the remainders at each step (used Stack.Push to store the values). Then, we write the remainders in reverse, starting at the bottom and appending to the right each time (loop thru the stack to print the values). – rahul sharma Mar 20 '19 at 17:21

score 4 · Answer 9 · answered Jul 09 '14 at 06:39

I know this answer would look similar to most of the answers already here, but I noticed just about none of them uses a for-loop. This code works, and can be considered simple, in the sense it will work without any special functions, like a ToString() with parameters, and is not too long as well. Maybe some prefer for-loops instead of just while-loop, this may be suitable for them.

public static string ByteConvert (int num)
{
    int[] p = new int[8];
    string pa = "";
    for (int ii = 0; ii<= 7;ii = ii +1)
    {
        p[7-ii] = num%2;
        num = num/2;
    }
    for (int ii = 0;ii <= 7; ii = ii + 1)
    {
        pa += p[ii].ToString();
    }
    return pa;
}

score 4 · Answer 10 · edited Nov 17 '18 at 07:12

using System;

class Program 
{
    static void Main(string[] args) {

        try {

            int i = (int) Convert.ToInt64(args[0]);
            Console.WriteLine("\n{0} converted to Binary is {1}\n", i, ToBinary(i));

        } catch(Exception e) {
            Console.WriteLine("\n{0}\n", e.Message);
        }
    }

    public static string ToBinary(Int64 Decimal) {
        // Declare a few variables we're going to need
        Int64 BinaryHolder;
        char[] BinaryArray;
        string BinaryResult = "";

        while (Decimal > 0) {
            BinaryHolder = Decimal % 2;
            BinaryResult += BinaryHolder;
            Decimal = Decimal / 2;
        }

        BinaryArray = BinaryResult.ToCharArray();
        Array.Reverse(BinaryArray);
        BinaryResult = new string(BinaryArray);

        return BinaryResult;
    }
}

You're reinventing the wheel here. The BCL already contains methods to do this. — Eltariel, Jun 02 '10 at 06:37

score 3 · Answer 11 · edited Nov 17 '18 at 08:06

class Program
{
    static void Main(string[] args)
    {
        var @decimal = 42;
        var binaryVal = ToBinary(@decimal, 2);

        var binary = "101010";
        var decimalVal = ToDecimal(binary, 2);

        Console.WriteLine("Binary value of decimal {0} is '{1}'", @decimal, binaryVal);
        Console.WriteLine("Decimal value of binary '{0}' is {1}", binary, decimalVal);
        Console.WriteLine();

        @decimal = 6;
        binaryVal = ToBinary(@decimal, 3);

        binary = "20";
        decimalVal = ToDecimal(binary, 3);

        Console.WriteLine("Base3 value of decimal {0} is '{1}'", @decimal, binaryVal);
        Console.WriteLine("Decimal value of base3 '{0}' is {1}", binary, decimalVal);
        Console.WriteLine();


        @decimal = 47;
        binaryVal = ToBinary(@decimal, 4);

        binary = "233";
        decimalVal = ToDecimal(binary, 4);

        Console.WriteLine("Base4 value of decimal {0} is '{1}'", @decimal, binaryVal);
        Console.WriteLine("Decimal value of base4 '{0}' is {1}", binary, decimalVal);
        Console.WriteLine();

        @decimal = 99;
        binaryVal = ToBinary(@decimal, 5);

        binary = "344";
        decimalVal = ToDecimal(binary, 5);

        Console.WriteLine("Base5 value of decimal {0} is '{1}'", @decimal, binaryVal);
        Console.WriteLine("Decimal value of base5 '{0}' is {1}", binary, decimalVal);
        Console.WriteLine();

        Console.WriteLine("And so forth.. excluding after base 10 (decimal) though :)");
        Console.WriteLine();


        @decimal = 16;
        binaryVal = ToBinary(@decimal, 11);

        binary = "b";
        decimalVal = ToDecimal(binary, 11);

        Console.WriteLine("Hexidecimal value of decimal {0} is '{1}'", @decimal, binaryVal);
        Console.WriteLine("Decimal value of Hexidecimal '{0}' is {1}", binary, decimalVal);
        Console.WriteLine();
        Console.WriteLine("Uh oh.. this aint right :( ... but let's cheat :P");
        Console.WriteLine();

        @decimal = 11;
        binaryVal = Convert.ToString(@decimal, 16);

        binary = "b";
        decimalVal = Convert.ToInt32(binary, 16);

        Console.WriteLine("Hexidecimal value of decimal {0} is '{1}'", @decimal, binaryVal);
        Console.WriteLine("Decimal value of Hexidecimal '{0}' is {1}", binary, decimalVal);

        Console.ReadLine();
    }


    static string ToBinary(decimal number, int @base)
    {
        var round = 0;
        var reverseBinary = string.Empty;

        while (number > 0)
        {
            var remainder = number % @base;
            reverseBinary += remainder;

            round = (int)(number / @base);
            number = round;
        }

        var binaryArray = reverseBinary.ToCharArray();
        Array.Reverse(binaryArray);

        var binary = new string(binaryArray);
        return binary;
    }

    static double ToDecimal(string binary, int @base)
    {
        var val = 0d;

        if (!binary.All(char.IsNumber))
            return 0d;

        for (int i = 0; i < binary.Length; i++)
        {
            var @char = Convert.ToDouble(binary[i].ToString());

            var pow = (binary.Length - 1) - i;
            val += Math.Pow(@base, pow) * @char;
        }

        return val;
    }
}

Learning sources:

Everything you need to know about binary

including algorithm to convert decimal to binary

Thanks for demonstrating ToDecimal() method as well. – Rajiv Jun 17 '17 at 08:13 — Rajiv, Jun 17 '17 at 08:13

Govind · Answer 12 · 2018-01-17T11:21:02.230

3

This function will convert integer to binary in C#:

public static string ToBinary(int N)
{
    int d = N;
    int q = -1;
    int r = -1;

    string binNumber = string.Empty;
    while (q != 1)
    {
        r = d % 2;
        q = d / 2;
        d = q;
        binNumber = r.ToString() + binNumber;
    }
    binNumber = q.ToString() + binNumber;
    return binNumber;
}

edited Jan 17 '18 at 11:21

answered Jan 17 '18 at 10:31

Govind

51
7

3

You should explain how your code answers the question. Please read SO guidelines before posting. – sparkitny Jan 17 '18 at 10:39
The above written code converts unsigned integer number into its binary string. – Govind Jan 17 '18 at 11:08

score 2 · Answer 13 · edited Mar 31 '14 at 22:00

class Program{

   static void Main(string[] args){

      try{

     int i = (int)Convert.ToInt64(args[0]);
         Console.WriteLine("\n{0} converted to Binary is {1}\n",i,ToBinary(i));

      }catch(Exception e){

         Console.WriteLine("\n{0}\n",e.Message);

      }

   }//end Main


        public static string ToBinary(Int64 Decimal)
        {
            // Declare a few variables we're going to need
            Int64 BinaryHolder;
            char[] BinaryArray;
            string BinaryResult = "";

            while (Decimal > 0)
            {
                BinaryHolder = Decimal % 2;
                BinaryResult += BinaryHolder;
                Decimal = Decimal / 2;
            }

            // The algoritm gives us the binary number in reverse order (mirrored)
            // We store it in an array so that we can reverse it back to normal
            BinaryArray = BinaryResult.ToCharArray();
            Array.Reverse(BinaryArray);
            BinaryResult = new string(BinaryArray);

            return BinaryResult;
        }


}//end class Program

David Chelliah · Answer 14 · 2017-11-19T21:33:43.207

BCL provided Convert.ToString(n, 2) is good, but in case you need an alternate implementation which is few ticks faster than BCL provided one.

Following custom implementation works for all integers(-ve and +ve). Original source taken from https://davidsekar.com/algorithms/csharp-program-to-convert-decimal-to-binary

static string ToBinary(int n)
{
    int j = 0;
    char[] output = new char[32];

    if (n == 0)
        output[j++] = '0';
    else
    {
        int checkBit = 1 << 30;
        bool skipInitialZeros = true;
        // Check the sign bit separately, as 1<<31 will cause
        // +ve integer overflow
        if ((n & int.MinValue) == int.MinValue)
        {
            output[j++] = '1';
            skipInitialZeros = false;
        }

        for (int i = 0; i < 31; i++, checkBit >>= 1)
        {
            if ((n & checkBit) == 0)
            {
                if (skipInitialZeros)
                    continue;
                else
                    output[j++] = '0';
            }
            else
            {
                skipInitialZeros = false;
                output[j++] = '1';
            }
        }
    }

    return new string(output, 0, j);
}

Above code is my implementation. So, I'm eager to hear any feedback :)

score 2 · Answer 15 · answered Nov 04 '22 at 10:22

2

Just one line for 8 bit

Console.WriteLine(Convert.ToString(n, 2).PadLeft(8, '0'));

where n is the number

answered Nov 04 '22 at 10:22

sam kihonge

173
3
5

trinalbadger587 · Answer 16 · 2014-01-27T14:24:35.433

1

    // I use this function
    public static string ToBinary(long number)
    {
        string digit = Convert.ToString(number % 2);
        if (number >= 2)
        {
            long remaining = number / 2;
            string remainingString = ToBinary(remaining);
            return remainingString + digit;
        }
        return digit;
     }

edited Jan 27 '14 at 14:24

answered Jan 18 '14 at 03:05

trinalbadger587

1,905
1
18
36

score 1 · Answer 17 · answered Mar 23 '17 at 15:32

        static void Main(string[] args) 
        {
        Console.WriteLine("Enter number for converting to binary numerical system!");
        int num = Convert.ToInt32(Console.ReadLine());
        int[] arr = new int[16];

        //for positive integers
        if (num > 0)
        {

            for (int i = 0; i < 16; i++)
            {
                if (num > 0)
                {
                    if ((num % 2) == 0)
                    {
                        num = num / 2;
                        arr[16 - (i + 1)] = 0;
                    }
                    else if ((num % 2) != 0)
                    {
                        num = num / 2;
                        arr[16 - (i + 1)] = 1;
                    }
                }
            }
            for (int y = 0; y < 16; y++)
            {
                Console.Write(arr[y]);
            }
            Console.ReadLine();
        }

        //for negative integers
        else if (num < 0)
        {
            num = (num + 1) * -1;

            for (int i = 0; i < 16; i++)
            {
                if (num > 0)
                {
                    if ((num % 2) == 0)
                    {
                        num = num / 2;
                        arr[16 - (i + 1)] = 0;
                    }
                    else if ((num % 2) != 0)
                    {
                        num = num / 2;
                        arr[16 - (i + 1)] = 1;
                    }
                }
            }

            for (int y = 0; y < 16; y++)
            {
                if (arr[y] != 0)
                {
                    arr[y] = 0;
                }
                else
                {
                    arr[y] = 1;
                }
                Console.Write(arr[y]);
            }
            Console.ReadLine();
        }           
    }

I know that the code is pretty basic and not too simple but working also with negative numbers — Kiril Dobrev, Mar 23 '17 at 15:37
You are receiving 32 bit integer, but your output array is of size - 16 bits. Just saying... — David Chelliah, Nov 19 '17 at 21:36
Yes, the remark is correct. It is right to use short for this code, but it works with int aswell. The example is with small numbers. If we want to use large numbers, the types must be changed. The idea is that if we want to work with negative numbers, the result should be at least one byte bigger so the program can see that this is an inverted additional code. — Kiril Dobrev, Nov 21 '17 at 12:48

score 1 · Answer 18 · answered Sep 23 '18 at 17:24

1

This might be helpful if you want a concise function that you can call from your main method, inside your class. You may still need to call int.Parse(toBinary(someint)) if you require a number instead of a string but I find this method work pretty well. Additionally, this can be adjusted to use a for loop instead of a do-while if you'd prefer.

    public static string toBinary(int base10)
    {
        string binary = "";
        do {
            binary = (base10 % 2) + binary;
            base10 /= 2;
        }
        while (base10 > 0);

        return binary;
    }

toBinary(10) returns the string "1010".

answered Sep 23 '18 at 17:24

Iona Erofeeff

9
3

This is pretty much the same as Govind's answer (which - to my surprise - is the only equivalent right-to-left iterative answer amongst all these answers) but you're right it's shorter and neater. That said, I'm not sure string prepending like this is going to be very efficient, and you're unlikely to beat the built-in method for efficiency anyway. I also can't see why you'd want to interpret this as an integer number again, but if you did you could do that by constructing the output out of powers of 10 in a similar method to this rather than via a string. – Rup Sep 23 '18 at 17:37

score 1 · Answer 19 · edited Jul 22 '19 at 17:04

I came across this problem in a coding challenge where you have to convert 32 digit decimal to binary and find the possible combination of the substring.

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Numerics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    class Program
    {

        public static void Main()
        {
            int numberofinputs = int.Parse(Console.ReadLine());
            List<BigInteger> inputdecimal = new List<BigInteger>();
            List<string> outputBinary = new List<string>();


            for (int i = 0; i < numberofinputs; i++)
            {
                inputdecimal.Add(BigInteger.Parse(Console.ReadLine(), CultureInfo.InvariantCulture));
            }
            //processing begins 

            foreach (var n in inputdecimal)
            {
                string binary = (binaryconveter(n));
                subString(binary, binary.Length);
            }

            foreach (var item in outputBinary)
            {
                Console.WriteLine(item);
            }

            string binaryconveter(BigInteger n)
            {
                int i;
                StringBuilder output = new StringBuilder();

                for (i = 0; n > 0; i++)
                {
                    output = output.Append(n % 2);
                    n = n / 2;
                }

                return output.ToString();
            }

            void subString(string str, int n)
            {
                int zeroodds = 0;
                int oneodds = 0;

                for (int len = 1; len <= n; len++)
                {

                    for (int i = 0; i <= n - len; i++)
                    {
                        int j = i + len - 1;

                        string substring = "";
                        for (int k = i; k <= j; k++)
                        {
                            substring = String.Concat(substring, str[k]);

                        }
                        var resultofstringanalysis = stringanalysis(substring);
                        if (resultofstringanalysis.Equals("both are odd"))
                        {
                            ++zeroodds;
                            ++oneodds;
                        }
                        else if (resultofstringanalysis.Equals("zeroes are odd"))
                        {
                            ++zeroodds;
                        }
                        else if (resultofstringanalysis.Equals("ones are odd"))
                        {
                            ++oneodds;
                        }

                    }
                }
                string outputtest = String.Concat(zeroodds.ToString(), ' ', oneodds.ToString());
                outputBinary.Add(outputtest);
            }

            string stringanalysis(string str)
            {
                int n = str.Length;

                int nofZeros = 0;
                int nofOnes = 0;

                for (int i = 0; i < n; i++)
                {
                    if (str[i] == '0')
                    {
                        ++nofZeros;
                    }
                    if (str[i] == '1')
                    {
                        ++nofOnes;
                    }

                }
                if ((nofZeros != 0 && nofZeros % 2 != 0) && (nofOnes != 0 && nofOnes % 2 != 0))
                {
                    return "both are odd";
                }
                else if (nofZeros != 0 && nofZeros % 2 != 0)
                {
                    return "zeroes are odd";
                }
                else if (nofOnes != 0 && nofOnes % 2 != 0)
                {
                    return "ones are odd";
                }
                else
                {
                    return "nothing";
                }

            }
            Console.ReadKey();
        }

    }
}

score 0 · Answer 20 · answered Nov 20 '17 at 07:03

    int x=550;
    string s=" ";
    string y=" ";

    while (x>0)
    {

        s += x%2;
        x=x/2;
    }


    Console.WriteLine(Reverse(s));
}

public static string Reverse( string s )
{
    char[] charArray = s.ToCharArray();
    Array.Reverse( charArray );
    return new string( charArray );
}

will_m · Answer 21 · 2021-01-03T06:26:47.067

This was a interesting read i was looking for a quick copy paste. I knew i had done this before long ago with bitmath differently.

Here was my take on it.

// i had this as a extension method in a static class (this int inValue);

public static string ToBinaryString(int inValue)
{
    string result = "";
    for (int bitIndexToTest = 0; bitIndexToTest < 32; bitIndexToTest++)
        result += ((inValue & (1 << (bitIndexToTest))) > 0) ? '1' : '0';
    return result;
}

You could stick spacing in there with a bit of modulos in the loop.

        // little bit of spacing
        if (((bitIndexToTest + 1) % spaceEvery) == 0)
            result += ' ';

You could probably use or pass in a stringbuilder and append or index directly to avoid deallocations and also get around the use of += this way;

did you test your method, it gives the binary string in reverse — Eboubaker, Nov 11 '21 at 18:34

score 0 · Answer 22 · edited Nov 26 '21 at 12:43

0

var b = Convert.ToString(i,2).PadLeft(32,'0').ToCharArray().Reverse().ToArray();

edited Nov 26 '21 at 12:43

Suraj Rao

29,388
11
94
103

answered Nov 26 '21 at 12:35

Omid Moridi

43
3

Convert integer to binary in C#

22 Answers22

Linked

Related