27 lines
435 B
C
27 lines
435 B
C
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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int main(int argc, char *argv[])
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{
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int fd;
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unsigned char tally = 0;
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unsigned char next = 0;
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if (argc!=2) return -1;
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fd = open(argv[1], O_RDWR|O_APPEND);
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if (fd<0) return -2;
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while (read(fd, &next, 1)) {
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//printf("Tally: %X, next byte: %X\n", tally, next);
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tally ^= next;
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};
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printf("Final tally: %X\n", tally);
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write(fd, &tally, 1);
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close(fd);
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return 0;
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}
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