# Introduction to the a simplified toy-DICOM file format I (Problems for the reader)

If you understand all what we have said about the binary and hexadecimal coding of alphanumeric characters then you would certainly solve the following Problems:

1. If we know that the bits 1100 represent a number, what number do they represent in hexadecimal form and in decimal form?
2. If we know that the half byte C represents a number, what number it is then in decimal form?
3. If we know that the half byte CC represents a number, what number it is then in decimal form?
4. If the two bytes 1F CC represent a number, can we tell what number it is without asking a question? What would that question be?
5. Regarding the previous problem, let us assume that the answer to the question is: The place values increase from the left to the right. What then is our number in question in decimal form?
6. If the answer is, as opposed to the previous answer: the place values increase from the left to the right. What is the number then in decimal form?
7. Let us take the following byte stream
11 01 1F 2A 11 11. :: Let as assume that these bytes represent a series of numbers. a) a. Is it possible to get the represented numbers without any questions? b) b. In order for us to be able decode this sequence what questions should be asked?
8. Let us suppose now that the answers are a) These are words. The decimal numbers at stake are represented by pairs of bytes. b) The place values increase from the right to the left c)Having answered the questions, give the 3 decimal numbers encoded in our byte stream above
9. Let us suppose that we have 3 special signs (bytes) 00, 11, FF. Then the task will be to decode a byte stream a) a. 00 tells us that the following byte in the stream represents one single decimal number, b) FF tells us that the following 2 bytes form a word, which represents a decimal number and the place values increase from the right to the left, c) 11 tells us that the following 3 bytes represent 3 Latin-2 characters d) Here is our byte sequence coded according to the rules given above
00 01 00 00 00 FF 00 B1 FF 00 00 FF 00 11 11 42 59 45 11 42 59 45
e) What would happen if because of some error we could not see the first byte? f) How do we know that an FF in the stream is a part of a number, or is it a symbol helping us in decoding our byte stream? g) g. Let us decode the byte stream given above