decimal to binary conversion program in java code example

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

// 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();
   }
}

Example 2: convert decimal to binary in java

public class DecimalToBinaryExample2{    
public static void toBinary(int decimal){    
     int binary[] = new int[40];    
     int index = 0;    
     while(decimal > 0){    
       binary[index++] = decimal%2;    
       decimal = decimal/2;    
     }    
     for(int i = index-1;i >= 0;i--){    
       System.out.print(binary[i]);    
     }    
System.out.println();//new line  
}    
public static void main(String args[]){      
System.out.println("Decimal of 10 is: ");  
toBinary(10);    
System.out.println("Decimal of 21 is: ");  
toBinary(21);    
System.out.println("Decimal of 31 is: ");    
toBinary(31);  
}}