# T.2. Tasks with Operators, Exceptions and OOP

The programming tasks for this block are as follows:

 1. ‹machine.*› – a simple register machine simulator,
 2. ‹natural.*› – arbitrary-size natural numbers,
 3. ‹parser.*› – parsing simplified JSON,
 4. ‹complex.*› – arbitrary-precision complex numbers.

The first task only relies on knowledge from the first block and you
should be able to start working on it immediately. Tasks 2 and 4
additionally require operator overloading (chapter 5) and basic
understanding of exceptions (chapter 6). Finally, task 3 needs
‹unique_ptr› (chapter 7) and virtual dispatch (chapter 8), but the
parser itself (and hence ‹xml_validate›) can be implemented with
knowledge from block 1 alone, so you can still start early.