In this tutorial, we will write a program to convert a decimal number into binary in java using recursion. Before that, you must have knowledge of the following topics in java.

**Binary number**

The binary numbers are based on 0 and 1, so it is a base 2 number. They are the combination of 0 and 1. For example, 1001, 110101, etc.

**Decimal Number**

These are the numbers with a base of 10, which ranges from 0 to 9. These numbers are formed by the combination of 0 to 9 digits such as 24, 345, etc.

Here is the chart where for the equivalent value of decimal and binary numbers.

**Example:**

`Input: 5 `

Output: 101

Input: 7

Output: 111

Now let us go through a program for the conversion of decimal to binary in java using recursive function.

**Java Program to Convert Decimal to Binary using Recursion**

**Source code:**

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | import java.io.*; import java.util.Scanner; public class Main { public static void main(String args[]) { int dec; Scanner in = new Scanner(System.in); System.out.println("Enter a decimal number: "); dec = in .nextInt(); System.out.print("Equivalent Binary Value: "); System.out.println(conversionFunc(dec)); //calling recursive function } //recursive function public static int conversionFunc(int decNumber) { if (decNumber == 0) return 0; else return (decNumber % 2 + 10* conversionFunc(decNumber / 2)); } } |

**Output:**

`Enter a decimal number:`

7

Equivalent Binary Value: 111