Simulate Cyclic Redundancy Check (CRC) error detection algorithm for noisy channel.

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#include<iostream>

#include<conio.h>

#include<stdlib.h>

using namespace std;

void calc(int* temp,int* gen,int size)

{

for(int i=0;i<size;i++)

{

if(temp[i]==gen[i])

temp[i]=0;

else

temp[i]=1;

}

}

int main()

{

int *msg,

*key;

int msize,ksize,i;

1

cout<<"\n eneter the size of key:";

cin>>ksize;

key=new int[ksize];

cout<<"\n enter key:";

for(i=0;i<ksize;i++)

cin>>key[i];

cout<<"\n enter the size of message:";

cin>>msize;

msg=new int[msize+ksize-1];

cout<<"\n enter message:";

for(i=0;i<msize;i++)

cin>>msg[i];

for(i=msize;i<msize+ksize-1;i++)

msg[i]=0;

int *temp=new int[ksize];

int *zkey=new int[ksize];

for(i=0;i<ksize;i++)

{ temp[i]=msg[i]; zkey[i]=0; }

for(i=ksize-1;i<msize+ksize-1;i++)

2

{

temp[ksize-1]=msg[i];

if(temp[0]==0)

calc(temp,zkey,ksize);

else

calc(temp,key,ksize);

for(int j=1;j<ksize;j++)

{ temp[j-1]=temp[j]; }

}

cout<<"\n crc is:";

for(i=0;i<ksize-1;i++)

cout<<temp[i];

for(int i=msize,j=0;i<ksize

+msize-1,j<ksize-1;i++,j++)

{

msg[i]=temp[j];

}

3

int n=rand()%(ksize+msize+5);

msg[n]=!msg[n];

cout<<"\n"<<n<<"\n";

for(i=0;i<ksize;i++)

{

temp[i]=msg[i]; zkey[i]=0; }

for(i=ksize-1;i<msize+ksize-1;i++)

{

temp[ksize-1]=msg[i];

if(temp[0]==0)

calc(temp,zkey,ksize);

else

calc(temp,key,ksize);

for(int j=1;j<ksize;j++)

{ temp[j-1]=temp[j]; }

}

for(int i=0;i<ksize-1;i++)

{ cout<<temp[i];

4

}

int flag=1;

for(int i=0;i<ksize-1;i++)

{ if(temp[i]==1)

flag=0;

}

if(flag==0)

cout<<"\nError";

else

cout<<"\nNo error";

getch();

return 0;

}

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Output:-