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HammingCode.java
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HammingCode.java
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package hammingCode;
import java.util.Scanner;
public class HammingCode {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sn=new Scanner(System.in);
System.out.println("Enter your data");
String binaryData=sn.nextLine();
System.out.println("Choose the parity");
System.out.println("1. even \n2. odd");
int ch=sn.nextInt();
int i;
for(i=0;i+4<=binaryData.length();i=i+4) {
String fourBit=binaryData.substring(i,i+4);
System.out.println("\nThe four bits are "+fourBit);
senderCode(fourBit,ch,sn);
}
if(binaryData.length()%4!=0) {
String bits=binaryData.substring(i,binaryData.length());
for(int j=bits.length();j<4;j++) {
bits="0"+bits;
}
System.out.println("\nThe four bits are "+bits);
senderCode(bits, ch, sn);
}
}
private static void senderCode(String fourBit, int ch, Scanner sn) {
// TODO Auto-generated method stub
int sevenBits[]=new int[8];
sevenBits[3]=(int)fourBit.charAt(0)-48;
sevenBits[5]=(int)fourBit.charAt(1)-48;
sevenBits[6]=(int)fourBit.charAt(2)-48;
sevenBits[7]=(int)fourBit.charAt(3)-48;
if(ch==1) {
if((sevenBits[3]+sevenBits[5]+sevenBits[7])%2==0) {
sevenBits[1]=0;
}
else {
sevenBits[1]=1;
}
if((sevenBits[3]+sevenBits[6]+sevenBits[7])%2==0) {
sevenBits[2]=0;
}
else {
sevenBits[2]=1;
}
if((sevenBits[5]+sevenBits[6]+sevenBits[7])%2==0) {
sevenBits[4]=0;
}
else {
sevenBits[4]=1;
}
}
else {
if((sevenBits[3]+sevenBits[5]+sevenBits[7])%2==0) {
sevenBits[1]=1;
}
else {
sevenBits[1]=0;
}
if((sevenBits[3]+sevenBits[6]+sevenBits[7])%2==0) {
sevenBits[2]=1;
}
else {
sevenBits[2]=0;
}
if((sevenBits[5]+sevenBits[6]+sevenBits[7])%2==0) {
sevenBits[4]=1;
}
else {
sevenBits[4]=0;
}
}
System.out.print("The sent data is ");
for(int i=1;i<=7;i++) {
System.out.print(sevenBits[i]);
}System.out.println();
System.out.println("Enter the probability of an error to occur");
double p=sn.nextFloat();
// random value for probability
double randProb=Math.random();
// random bit position
int randBitPos=0;
while(randBitPos<1 || randBitPos>7) {
randBitPos=(int)Math.ceil(Math.random()*10);
//System.out.println(randBitPos);
}
//System.out.println("random prob = "+randProb);
//System.out.println("random bit pos = "+randBitPos);
if (randProb<=p) {
if(sevenBits[randBitPos]==1) {
sevenBits[randBitPos]=0;
}
else {
sevenBits[randBitPos]=1;
}
}
System.out.print("The recieved data is ");
for(int i=1;i<=7;i++) {
System.out.print(sevenBits[i]);
}System.out.println();
//check for error
String parityCode="";
if(ch==1) {
if((sevenBits[1]+sevenBits[3]+sevenBits[5]+sevenBits[7])%2==0) {
parityCode+="0";
}else {
parityCode+="1";
}
if((sevenBits[2]+sevenBits[3]+sevenBits[6]+sevenBits[7])%2==0) {
parityCode="0"+parityCode;
}else {
parityCode="1"+parityCode;
}
if((sevenBits[4]+sevenBits[5]+sevenBits[6]+sevenBits[7])%2==0) {
parityCode="0"+parityCode;
}else {
parityCode="1"+parityCode;
}
}
else {
if((sevenBits[1]+sevenBits[3]+sevenBits[5]+sevenBits[7])%2==0) {
parityCode+="1";
}else {
parityCode+="0";
}
if((sevenBits[2]+sevenBits[3]+sevenBits[6]+sevenBits[7])%2==0) {
parityCode="1"+parityCode;
}else {
parityCode="0"+parityCode;
}
if((sevenBits[4]+sevenBits[5]+sevenBits[6]+sevenBits[7])%2==0) {
parityCode="1"+parityCode;
}else {
parityCode="0"+parityCode;
}
}
int decimalValue = Integer.parseInt(parityCode, 2);
if(decimalValue==0) {
System.out.println("No error found");
}
else {
System.out.println("The error is found at position "+decimalValue);
if(sevenBits[decimalValue]==1) {
sevenBits[decimalValue]=0;
}
else {
sevenBits[decimalValue]=1;
}
System.out.print("The corrected codeword is ");
for(int i=1;i<=7;i++) {
System.out.print(sevenBits[i]);
}System.out.println();
}
}
}