/* PBXA64 handbook-style C text example: checksum_xor.
 * calculate an XOR packet checksum over a text payload. This source deliberately keeps every transformation visible
 * instead of hiding it behind library calls, making it useful for tracing.
 */
int main(void) {
    char s[] = "packet"; unsigned char sum = 0; int i = 0; for (i = 0; s[i] != 0; ++i) sum ^= (unsigned char)s[i]; return sum == 0 ? 1 : 0;
}

/* Discussion: inspect the loop bounds, byte classification, and final return
 * value. The bounded-C frontend currently records CIR0200 for all C source;
 * this example remains a real handbook program for the public C surface once
 * that frontend gate is restored. */
