Sem 5‎ > ‎DCCN LAB‎ > ‎

P-3 WAP to generate Hamming Code.

posted Nov 6, 2012, 8:50 AM by Neil Mathew
SOURCE CODE:


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#include <iostream> 
//#include<conio.h> 
 
using namespace std;
 
// HAMMING CODE FOR 4-bit data. 2^2 => 2 + 1 = 3
// Error detection bits req = 3
// Total bits required = 4 + 3 = 7 bits
 
// R holding the error detection bits.
// 2^0 = 1
// 2^1 = 2
// 2^2 = 4
 
// Frame: d7 d6 d5 r4 d3 r2 r1
 
int i=0;
int d3, d5, d6, d7;
int r1, r2, r4;
 
 
void sender()
{
        cout<<" Enter the 4-bit word: ";
        cin>>d7;
        cin>>d6;
        cin>>d5;
        cin>>d3;
 
// What all positions it affects:
// r1: 1, 3, 5, 7
// r2: 2, 3, 6, 7
// r4: 4, 5, 6, 7
 
// Then, check whether it contains even number of 1s or not.
// If even, put 0, else put 1.
 
        r1= (d3 + d5 + d7) %2;
        r2= (d3 + d6 + d7) %2;
        r4= (d5 + d6 + d7) %2;
 
// FRAME:
        int frame[] = { r1, r2, d3, r4, d5, d6, d7 };
 
        cout <<"\n The code at SENDER is: ";
        for(i=6; i>=0; i--)
        cout<<frame[i]<<" ";
}
 
void receiver()
{
        int frame[7];
        cout<<"\n Enter the code at RECEIVER: ";
 
        for(i=6; i>=0; i--)
        cin>>frame[i];
 
        d7 = frame[6];
        d6 = frame[5];
        d5 = frame[4];
        r4 = frame[3];
        d3 = frame[2];
        r2 = frame[1];
        r1 = frame[0];
 
// What all positions Rs it affects:
// r1: 1, 3, 5, 7
// r2: 2, 3, 6, 7
// r4: 4, 5, 6, 7
 
        //If not even
        r1= (r1 + d3 + d5 + d7) %2;
        r2= (r2 + d3 + d6 + d7) %2;
        r4= (r4 + d5 + d6 + d7) %2;
 
//Find position by converting binary no r4 r2 r1 to decimal
 
        int dec=0;
 
        if( r1 == 0 && r2 == 0 && r4 == 0 )
        cout<<" No Errors. Message is = "<<d7<<d6<<d5<<d3;
        else
        {
        if( r4 == 1)
        dec += 4;
 
        if(r2 == 1)
        dec += 2;
 
        if(r1 == 1)
        dec += 1;
 
        cout<<"\n Error found at position "<<dec;
        }
}
 
int main ( )
{
//      clrscr();
 
        cout<<"\n FRAME: d7 d6 d5 r4 d3 r2 r1 "<<endl;
        cout<<endl;
        sender();
 
        cout<<endl;
        receiver();
        cout<<endl;
//      getch();
}


OUTPUT:

 FRAME: d7 d6 d5 r4 d3 r2 r1 

 Enter the 4-bit word: 1 1 0 0
 The code at SENDER is: 1 1 0 0 0 0 1 

 Enter the code at RECEIVER: 1 1 0 0 0 0 1 
 No Errors. Message is = 1100
 FRAME: d7 d6 d5 r4 d3 r2 r1 

 Enter the 4-bit word: 1 1 0 0
 The code at SENDER is: 1 1 0 0 0 0 1 

 Enter the code at RECEIVER: 1 1 0 0 1 0 1
 Error found at position 3
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