Erik did write 030h which is hexadecimal and written 0x30 in C. The corresponding decimal value is 48, but it is better to write '0' and let the compiler worry about the numeric value for the '0' character.

If you have a number 1388 stored in BCD format, i.e. four bits/digit, then you convert as:

long value = 0x1388;
digit1 = ((value >> 12) & 0x0f) + '0';
digit2 = ((value >> 8) & 0x0f) + '0';
digit3 = ((value >> 4) & 0x0f) + '0';
digit4 = (value & 0x0f) + '0';

If you the value was stored in binary form, then you convert as:

long value = 1388;
digit1 = (value / 1000) + '0';
digit2 = ((value / 100) % 10) + '0';
digit3 = ((value / 10) % 10) + '0';
digit4 = (value % 10) + '0';