Calculation Of CRC C++ Program

Calculation Of CRC

/* Calculation of CRC (Cyclic Redundancy Check)*/

#include< stdlib.h>
#include< conio.h>
#include< stdio.h>
void main()
{
 int i,j,n,g,a,arr[20],gen[20],b[20],q[20],s;
 clrscr();
 printf("Transmitter side:");
 printf("\nEnter no. of data bits:");
 scanf("%d",&n);
 printf("Enter data:");
 for(i=0;i< n;i++)
  scanf("%d",&arr[i]);

 printf("Enter size of generator:");
 scanf("%d",&g);
 do{
  printf("Enter generator:");
  for(j=0;j< g;j++)
  scanf("%d",&gen[j]);
 }
 while(gen[0]!=1);
 printf("\n\tThe generator matrix:");
 for(j=0;j< g;j++)
  printf("%d",gen[j]);

 a=n+(g-1);
 printf("\n\tThe appended matrix is:");
 for(i=0;i< j;++i)
  arr[n+i]=0;

 for(i=0;i< a;++i)
  printf("%d",arr[i]);

 for(i=0;i< n;++i)
  q[i]= arr[i];

 for(i=0;i< n;++i)
 {
  if(arr[i]==0)
  {
  for(j=i;j< g+i;++j)
   arr[j] = arr[j]^0;
  }
  else
  {
   arr[i] = arr[i]^gen[0];
   arr[i+1]=arr[i+1]^gen[1];
   arr[i+2]=arr[i+2]^gen[2];
   arr[i+3]=arr[i+3]^gen[3];
  }
 }
 printf("\n\tThe CRC is :");
 for(i=n;i < a;++i)
  printf("%d",arr[i]);
 s=n+a;
 for(i=n;i< s;i++)
  q[i]=arr[i];
 printf("\n");
 for(i=0;i< a;i++)
  printf("%d",q[i]);
 getch();
}
/* Output

Transmitter side:
Enter no. of data bits:8
Enter data:1 0 1 0 0 0 0 1
Enter size of generator:4
Enter generator:1 0 0 1

The generator matrix:1001
The appended matrix is:10100001000
The CRC is :111
10100001111
*/