How to convert a number from Decimal to Binary using recursion in C#?

To get the binary of Decimal, using recursion, firstly set the decimal number −

int dec = 30;

Now pass the value to a function −

public int displayBinary(int dec) { }

Now, check the condition until the decimal value is 0 and using recursion get the mod 2 of the decimal num as shown below. The recursive call will call the function again with the dec/2 value −

public int displayBinary(int dec) {    int res;    if (dec != 0) {       res = (dec % 2) + 10 * displayBinary(dec / 2);       Console.Write(res);       return 0;    } else {       return 0;    } }

The following is the complete code −

Example

 Live Demo

using System; public class Program {    public static void Main(string[] args) {       int dec;       Demo d = new Demo();       dec = 30;       Console.Write("Decimal = "+dec);       Console.Write("
Binary of {0} = ", dec);       d.displayBinary (dec);       Console.ReadLine();       Console.Write("
");    } } public class Demo {    public int displayBinary(int dec){       int res;       if (dec != 0) {          res = (dec % 2) + 10 * displayBinary(dec / 2);          Console.Write(res);          return 0;       } else {          return 0;       }    } }

Output

Decimal = 30 Binary of 30 = 11110