Signed and Unsigned Decimal to Binary number

It explains how to converts a number from decimal number (base 10) to binary numbers (base 2). The decimal value can be a unsigned (positive) or a signed (negative) decimal numbers. The binary operation, 2's complements used in conversion signed decimal value to binary.

signed/unsigned decimal to Binary Conversion - algorithm

• Initialize binary-bits array
• Read a decimal-value (positive or negative)
• value2 = abs(decimal-value)
• binary-bits = converts value2 into binary
• IF decimal-value >= 0
•    print binary-bits
• ELSE  binary-bits_2'sc = take 2's_complement on binary-bits
•    print binary-bits_2'sc

unsigned decimal to Binary Conversion - example

   The given positive decimal value is  decval=5; converts into binary  4 bits             
        decimal to binary 4 bit conversion steps
              1. bits = decval % 2;  
              2. decval = decval/2

           bits[4]  = 5  % 2  = 1;  decval = 5/2 = 2
           bits[3]  = 2  % 2  = 0;  decval = 2/2 = 1
           bits[2]  = 1  % 2  = 1;   decval = 1/2 = 0
           bits[1]  = 0  % 2  = 0;   decval = 1/2 = 0

      IF the decimal value is positive , no need 2's complement operation     
           then conversion result is binary bits = 0101              
      

signed decimal to Binary Conversion - example

   The given negative decimal value is  decval=-5; converts into binary  4 bits             

        decimal to binary 4 bit conversion steps
              1. take abs(decval)
              2. bits = decval % 2;  
              3. decval = decval/2
           
           decval=abs(decval) =5

           from above positive decimal to binary conversion  
                    bits[1-4]  = 0101  
          

  IF the given decimal value is negative, then takes 2's complement operation 
                                                 on converted binary bits
        
        2's complement on binary bits steps
            1. take 1's complement 
            2. binary addition  - add 1 with 1's complement result 
   
         Decimal to binary conversion results bits = 0101

            1's complement on bits 0101  = 1010

            add 1 with 1's complement results

                                     1010
                                     0001
                                    -------  
                  2's complement =   1011 
            
       signed decimal value -5 binary bits is =1011              
      

signed/unsigned Decimal To Binary Conversion - Java program

The Java program converts positive or negative decimal into binary numbers. For simplification. It is limited to binary 4 bits conversion. therefore, a decimal positive value must be between [0 to 8] and negative value between [-1 to -7].

 
import java.util.Scanner;

public class SignDecimal 
{
 
     public static String int2binary(int decval)
      {  
        StringBuffer sbuf =new StringBuffer();
        int nbits=4;
  
       for(int n=0;n<nbits;n++) 
        {
        sbuf.append( decval % 2 ) ;
        decval = decval /2;      
        }      
       return sbuf.reverse().toString();
    }
   
    public static void main(String[] args) 
     {    
      Scanner sc=new Scanner(System.in);
      System.out.println("signed and unsigned decimal to Binary Conversion");
  
      System.out.println("Enter Integer between [-7 to 8] ");  
      int val=sc.nextInt();
      sc.close();
  
      String binary="";
     if ( val < 0  ) 
      {    
       int val2 = Math.abs(val);
       binary=SignDecimal.int2binary(val2);     
       binary=Complement.twos(binary);       
     }
    else
    {
     binary=SignDecimal.int2binary(val);
    }
  
    System.out.println("Integer value :" + val);
    System.out.println("Binary Bits : " + binary);      
  }

}


 

signed & unsigned Decimal To Binary Conversion - Java program output

signed & unsigned decimal to Binary Conversion
Enter Integer between [-7 to 8] 
-6
Integer value :-6
Binary Bits : 1010

signed & unsigned decimal to Binary Conversion
Enter Integer between [-7 to 8] 
6
Integer value :6
Binary Bits : 0110