//
// Created by ajay on 10/16/17.
//

#include <stdio.h>
int datalen,divlen,res1[7],j,fin[7],net[7],dmp[1],rem[7];

int comp(int i, int j) {
    if(i == j){
        return 0;
    } else{
        return 1;
    }
}

void crc(int data[],int div[]) {
    for(int i = 0;i < datalen - divlen + 1; i++) {
        if(i == 0) {
            for(int p = 0;p < divlen; p++) {
                res1[p] = data[p];
            }
        }
        if(res1[0] != 0) {
            for(int p = 0; p < divlen; p++) {
                net[p] = comp(res1[p], div[p]);
            }
        }
        if(res1[0] == 0) {
            for(int p = 0;p < divlen; p++) {
                net[p] = comp(res1[p], dmp[0]);
            }
        }
        fin[i] = res1[0];
        for(int p = 0;p < divlen - 1; p++) {
            rem[p] = net[p+1];
        }
        if(i != datalen + divlen - 2) {
            for(int p = 0;p < divlen - 1; p++) {
                res1[p] = rem[p];
            }
            res1[divlen - 1] = data[divlen + i];
        }
    }
    printf("\nquotient is :\n");
    for(int p = 0; p < datalen - divlen + 1; p++) {
        printf("%d",fin[p]);
    }
    printf("\nThe remainder is :\n");
    for(int p = 0; p < divlen - 1; p++) {
        printf("%d", rem[p]);
    }
}

int main() {
    int data[21], datatemp[30], div[7], get = 0, templen;
    dmp[0] = 0;
    printf("Enter length of Data: ");
    scanf("%d", &datalen);
    templen=datalen;
    printf("\nEnter bits values: ");
    for(int e = 0;e < templen; e++) {
        scanf("%d", &data[e]);
        datatemp[e] = data[e];
    }
    printf("\nEnter divisor length : ");
    scanf("%d", &divlen);
    datalen+=divlen-1;
    printf("\nEnter bits values: ");
    for(int e = 0; e < divlen; e++) {
        scanf("%d",&div[e]);
    }
    for(int e = 0; e < divlen - 1; e++) {
        datatemp[templen+e] = 0;
    }
    printf("\nCRC GENERATOR\n");
    crc(datatemp,div);
    for(int e=0; e <divlen - 1; e++) {
        datatemp[templen+e] = rem[e];
    }
    printf("\nCRC CHECKER\n");
    crc(datatemp, div);
    for(int e = 0;e < divlen - 1; e++) {
        get += rem[e];
    }
    if(get == 0) {
        printf("\nData is Correct !!!\n");
    }
    else{
        printf("\nError in Data\n");
    }
}