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CRC 2

This document is a C program that implements the Cyclic Redundancy Check (CRC) algorithm for error detection in data transmission. It includes functions for performing XOR operations, computing the CRC remainder, and verifying received data against the CRC. The program prompts the user to input binary data and a generator polynomial, calculates the CRC, and checks for errors upon data reception.

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13 views3 pages

CRC 2

This document is a C program that implements the Cyclic Redundancy Check (CRC) algorithm for error detection in data transmission. It includes functions for performing XOR operations, computing the CRC remainder, and verifying received data against the CRC. The program prompts the user to input binary data and a generator polynomial, calculates the CRC, and checks for errors upon data reception.

Uploaded by

enjoybaap6
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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#include <stdio.

h>
#include <string.h>

#define MAX 100

// Perform XOR between dividend and divisor


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

// Compute CRC remainder


void computeCRC(char *data, char *key, char *remainder) {
int dataLen = strlen(data);
int keyLen = strlen(key);
char temp[MAX];

// Append n-1 zeros to the data


strcpy(temp, data);
for (int i = 0; i < keyLen - 1; i++) {
temp[dataLen + i] = '0';
}
temp[dataLen + keyLen - 1] = '\0';

strncpy(remainder, temp, keyLen);


remainder[keyLen] = '\0';

for (int i = 0; i < dataLen; i++) {


if (remainder[0] == '1') {
xorOperation(remainder, key, keyLen);
} else {
xorOperation(remainder, "0000000000000000", keyLen);
}

for (int j = 0; j < keyLen - 1; j++) {


remainder[j] = remainder[j + 1];
}
remainder[keyLen - 1] = temp[i + keyLen];
}
}

// Receiver side: verify received data


int checkCRC(char *received, char *key) {
char remainder[MAX];
computeCRC(received, key, remainder);

// If remainder is all zero, no error


for (int i = 0; i < strlen(key) - 1; i++) {
if (remainder[i] != '0') {
return 0; // Error found
}
}
return 1; // No error
}

int main() {
char data[MAX], key[MAX], transmitted[MAX], crcRemainder[MAX];

printf("Sender Side:\n");
printf("Enter data (binary): ");
scanf("%s", data);
printf("Enter key (generator polynomial in binary): ");
scanf("%s", key);

// Sender side CRC calculation


computeCRC(data, key, crcRemainder);

// Append CRC to data


strcpy(transmitted, data);
strcat(transmitted, crcRemainder);

printf("\nTransmitted Data (Data + CRC): %s\n", transmitted);

// Receiver side
printf("\nReceiver Side:\n");
char received[MAX];
printf("Enter received data: ");
scanf("%s", received);

if (checkCRC(received, key)) {
printf("No error detected. Data received correctly.\n");
} else {
printf("Error detected in received data!\n");
}

return 0;
}

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