Implementation of CRC

Implementation of CRC

 #include <stdio.h>

 #include <conio.h>

 #include <string.h>

 void main() {

                     int i,j,keylen,msglen;

     char input[100],key[30],temp[30],quot[100],rem[30],key1[30];

                clrscr();

        printf("Enter Data: ");

        gets(input);

        printf("Enter Key: ");

        gets(key);

        keylen=strlen(key);

        msglen=strlen(input);

        strcpy(key1,key);

        for (i=0;i<keylen-1;i++) {

                input[msglen+i]='0';

        }

        for (i=0;i<keylen;i++)

         temp[i]=input[i];

        for (i=0;i<msglen;i++) {

                quot[i]=temp[0];

                if(quot[i]=='0')

                 for (j=0;j<keylen;j++)

                 key[j]='0'; else

                 for (j=0;j<keylen;j++)

                 key[j]=key1[j];

                for (j=keylen-1;j>0;j--) {

                        if(temp[j]==key[j])

                         rem[j-1]='0'; else

                         rem[j-1]='1';

                }

                rem[keylen-1]=input[i+keylen];

                strcpy(temp,rem);

        }

        strcpy(rem,temp);

        printf("\nQuotient is ");

        for (i=0;i<msglen;i++)

         printf("%c",quot[i]);

        printf("\nRemainder is ");

        for (i=0;i<keylen-1;i++)

         printf("%c",rem[i]);

        printf("\nFinal data is: ");

        for (i=0;i<msglen;i++)

         printf("%c",input[i]);

        for (i=0;i<keylen-1;i++)

         printf("%c",rem[i]);

      getch();

}

CRC OUTPUT