# Java program to convert decimal number to binary & count number of 1s

Let’s learn java program to convert decimal number to binary & count number of 1s.

## Java program to convert decimal number to binary & count number of 1s

Java program to convert decimal to binary is the most common java interview question.

In java program to convert decimal to binary first user enters an integer number as an input using nextInt() method of scanner class.

This user input is stored in integer variable ‘number’. Then to convert from decimal to binary we use division operator and modulus operator along with while loop and if statement to get the output.

Here’s the java program to convert decimal to binary using while loop.

```// decimal to binary conversion in java
import java.util.Scanner;
public class DecimalBinaryDemo
{
public static void main(String[] args)
{
int number, count = 0, temp;
String strConvert = "";
Scanner sc = new Scanner(System.in);
System.out.println("Enter a decimal number : ");
number = sc.nextInt();
// decimal to binary java
while(number > 0)
{
temp = number % 2;
if(temp == 1)
{
count++;
}
strConvert = strConvert + " " + temp;
number = number / 2;
}
System.out.println("Decimal to binary in java : " + strConvert);
System.out.println("Number of 1s : " + count);
sc.close();
}
}

```

Output:

Enter a decimal number : 266
Decimal to binary in java : 0 1 0 1 0 0 0 0 1
Number of 1s : 3