Introduction to Microservice Architecture Using SpringBoot - Part 1

Checksum

• In checksum error detection scheme, the data is divided into k segments each of m bits.
• In the sender’s end the segments are added using 1’s complement arithmetic to get the sum. The sum is complemented to get the checksum.
• The checksum segment is sent along with the data segments.
• At the receiver’s end, all received segments are added using 1’s complement
arithmetic to get the sum. The sum is complemented.
• If the result is zero, the received data is accepted; otherwise discarded.

CODE 

 import java.util.*;  
 public class Checksum  
 {  
   public static void main(String[] args)  
   {  
     System.out.println("Enter 16 bits Data :");  
     Scanner sc= new Scanner(System.in);  
     String s=sc.nextLine();  
     String senddata=send(s);  
     System.out.println("Send Data :"+ senddata);  
     receive(senddata);  
   }  
   public static String send(String s)  
   {  
     String s1=s.substring(0,8);  
     String s2=s.substring(8);  
     String total=add(s1,s2);  
     String checksum=getcomplement(total);  
     System.out.println("CheckSum :"+checksum);  
     return s+checksum;  
   }  
   public static void receive(String s)  
   {  
     String s1=s.substring(0,8);  
     String s2=s.substring(8,16);  
     String s3=s.substring(16);  
     String sum=add(s1,s2);  
     sum=add(s3,sum);  
     String complement=getcomplement(sum);  
     System.out.println("receiver sum :"+sum);  
     System.out.println("receiver sum complement :"+complement);  
     if(complement.equals("00000000"))  
     System.out.println("data receive correctly");  
     else  
     System.out.println("data receive wrong");  
   }  
   public static String add(String s1, String s2)  
   {  
     String sum="";  
     int carry=0;  
     String[] str1=s1.split("");  
     String[] str2=s2.split("");  
     for(int i=str1.length-1;i>=0;i--)  
     {  
       int a=Integer.parseInt(str1[i]);  
       int b=Integer.parseInt(str2[i]);  
       int total=a^b^carry;  
       carry=(a&b)|(b&carry)|(carry&a);  
       sum=String.valueOf(total)+sum;  
     }  
     if(carry==1)  
     {  
       sum=add(sum ,"00000001");  
     }  
     return sum;  
   }  
   public static String getcomplement(String s)  
   {  
     s=s.replaceAll("1","X");  
     s=s.replaceAll("0","1");  
     s=s.replaceAll("X","0");  
     return s;  
   }  
 }  

OUTPUT

Enter 16 bits Data :

1111000011110000

CheckSum :00011110

Send Data :111100001111000000011110

receiver sum :11111111

receiver sum complement :00000000

data receive correctly