TDD folks will ask you to write tests first, then code. At least, for the example you used to make your question concrete, I'd first collect data I can use for testing before writing test code. You can even ask around for data.
Doing this helps me a lot 'cos by the time I have the data collected, I usually have a rather good idea of what code to write and edge cases even before writing a slew of tests for it.
If you're writing a data structure + algos for it, then think of a data format for storing and loading that structure so you can do the data collection in that format first. It'll also help write tests greatly.
Scripting languages are great ways to test your code, even if it is in C/C++. Learning to bind native code to some scripting language such as python helps a ton.
Doing this helps me a lot 'cos by the time I have the data collected, I usually have a rather good idea of what code to write and edge cases even before writing a slew of tests for it.
If you're writing a data structure + algos for it, then think of a data format for storing and loading that structure so you can do the data collection in that format first. It'll also help write tests greatly.
Scripting languages are great ways to test your code, even if it is in C/C++. Learning to bind native code to some scripting language such as python helps a ton.