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error detection using crc

#include <stdio.h>
#include <string.h>

#define N 100

void xorOperation(char *dividend, const char *divisor) {
    for (int i = 0; i < strlen(divisor); i++)
        dividend[i] = (dividend[i] == divisor[i]) ? '0' : '1';
}

void divide(char *data, const char *divisor, char *remainder) {
    int dataLen = strlen(data);
    int divisorLen = strlen(divisor);
    
    char temp[N];
    strncpy(temp, data, divisorLen);
    temp[divisorLen] = '\0';

for (int i = 0; i <= dataLen - divisorLen; i++) {
        if (temp[0] == '1')
            xorOperation(temp, divisor);
        
        if (i + divisorLen < dataLen)
            memmove(temp, temp + 1, divisorLen - 1), temp[divisorLen - 1] = data[i + divisorLen];
    }
    
    strcpy(remainder, temp);
}

void encode(char *data, const char *divisor) {
    int dataLen = strlen(data);
    int divisorLen = strlen(divisor);

char temp[N];
    strcpy(temp, data);
    strcat(temp, "000");  // Append zero bits

char remainder[N];
    divide(temp, divisor, remainder);

for (int i = 0; i < divisorLen - 1; i++)
        data[dataLen + i] = remainder[i];

data[dataLen + divisorLen - 1] = '\0';
}

int checkError(char *received, const char *divisor) {
    char remainder[N];
    divide(received, divisor, remainder);
    return (strchr(remainder, '1') == NULL);
}

int main() {
    char data[N] = "1101";
    char divisor[N] = "1011";
    
    printf("Original Data: %s\n", data);
    
    encode(data, divisor);
    printf("Transmitted Codeword: %s\n", data);
    
    // Test without error
    printf("Received Codeword: %s\n", data);
    printf("Error Detection: %s\n", checkError(data, divisor) ? "No Error" : "Error Detected");

// Introduce error
    data[2] = (data[2] == '1') ? '0' : '1';
    printf("Received Codeword (with error): %s\n", data);
    printf("Error Detection: %s\n", checkError(data, divisor) ? "No Error" : "Error Detected");

return 0;
}