void UART_ConvertDistance(unsigned long n){
// as part of Lab 11 you implemented this function


    short i = 0, j = 0;
    unsigned short str_len;
    unsigned char reverse_str[15];
    unsigned long m = n;

    if (m == 0) {
        str_len = 1;
        String[0] = 0x30;
        return;
    }

    while (m != 0) {
        reverse_str[j] = m % 10 + 0x30;
        m /= 10;
        j++;
    }

    str_len = j;

    for (j = str_len - 1; j >= 0; j--) {
        String[i] = reverse_str[j];
        // the last digit in reverse_str[10] is the first one in String[10]
        i++; // increase the index of String[10]
    }

    // second, go over each case
    // n has 1 digits
    if (n <= 9) {
        String[4] = String[0];
        String[0] = 0x30;
        String[1] = '.';
        String[2] = 0x30;
        String[3] = 0x30;
        String[5] = 0x20;
        String[6] = 'c';
        String[7] = 'm';
    }
    // n has 2 digits
    else if ((n >= 10) && (n <= 99)) {
        String[4] = String[1];
        String[3] = String[0];
        String[0] = 0x30;
        String[1] = '.';
        String[2] = 0x30;
        String[5] = 0x20;
        String[6] = 'c';
        String[7] = 'm';
    }
    // n has 3 digits
    else if ((n >= 100) && (n <= 999)) {
        String[4] = String[2];
        String[3] = String[1];
        String[2] = String[0];
        String[0] = 0x30;
        String[1] = '.';
        String[5] = 0x20;
        String[6] = 'c';
        String[7] = 'm';
    }
    // n has 4 digits
    else if ((n >= 1000) && (n <= 9999)) {
        String[4] = String[3];
        String[3] = String[2];
        String[2] = String[1];
        String[1] = '.';
        String[5] = 0x20;
        String[6] = 'c';
        String[7] = 'm';
    }
    // n has more than 4 digits (Overflow)
    else {
        String[0] = '*';
        String[1] = '.';
        String[2] = '*';
        String[3] = '*';
        String[4] = '*';
        String[5] = 0x20;
        String[6] = 'c';
        String[7] = 'm';
    }
}