TO IMPLEMENT CHECKSUM IN JAVA.

/*

TOPIC:TO IMPLEMENT CHECKSUM.

*/
import java.util.*;
class checksum
{
static int check[]=new int[4];
static int code[]=new int[12];
public static void add( int a[],int n)
{
int i,j=0;
for(i=0;i<4;i++)
{
if((a[i]==1 &&a[i+4]==1)||(a[i]==0&&a[i+4]==0))
{
check[i]=0;
}
else
{
check[i]=1;
}
}
for(i=0;i<n;i++)
{
code[i]=a[i];
}
while(j<4)
{
code[i]=check[j];
i++;j++;
}
}
public static void readd(int code[],int n)
{
int i,j=0,flag=0;
for(i=0;i<4;i++)
{
if((code[i]==1 && code[i+4]==1)||(code[i]==0&& code[i+4]==0))
check[i]=0;
else
check[i]=1;
}
i=i+4;
while(j<4)
{
if((code[i]==1&& check[j]==0)||(code[i]==0&&check[j]==1))
{
flag=1;
break;
}
i++;j++;
}
if(flag==1)
System.out.println("error present");
else
System.out.println("no error");
}

public static void main(String args[])
{
int a[]=new int[8];
Scanner sc=new Scanner(System.in);
System.out.println("enter 8bit word 1 by 1");
for(int i=0;i<8;i++)
{
a[i]=sc.nextInt();
}
add(a,a.length);
System.out.println("code sent");
for(int i=0;i<12;i++)
System.out.println("  "+code[i]);
System.out.println("\n\n enter recieved code 1 by 1");
for(int i=0;i<12;i++)
code[i]=sc.nextInt();
readd(code,code.length);
}
}
/*
OUTPUT:
enter 8bit word 1 by 1
1
1
1
1
1
1
1
1
code sent
  1
  1
  1
  1
  1
  1
  1
  1
  0
  0
  0
  0


 enter recieved code 1 by 1
1
1
1
1
1
1
1
1
1
0
0
0
error present
*/