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

int fromhex(char c) {
    if (c >= '0'  &&  c <= '9') return c - '0';
    else if (c >= 'A'  &&  c <= 'F') return c - 'A' + 10;
    else return c - 'a' + 10;
}

void asciify(const char *s)
{
    char result[strlen(s)+1];
    int r = 0;

    if (s[0] == '0'  &&  toupper(s[1]) == 'X') {
        s += 2;
    } else {
        // fixme base 10
    }
    
    char prev = 0;
    if (strlen(s) % 2 == 1) prev = '0';  // synthesize leading zero
    for ( ; *s; s++) {
        if (!prev) {
            prev = *s;
        } else if (!isxdigit(*s)) {
            prev = 0;
        } else {
            // printf("%c%c %x %x\n", prev, *s, fromhex(prev), fromhex(*s));
            int num = fromhex(prev)*16 + fromhex(*s);
            result[r++] = isgraph(num) ? num : ' ';
            prev = 0;
        }
    }
    result[r++] = '\0';

    printf("###%s###\n", result);
    printf("###");
    while (r--) {
        printf("%c", result[r]);
    }
    printf("###\n");
}


int main(int argc, char **argv)
{
    for (int i = 1; i < argc; i++) {
        asciify(argv[i]);
    }
}