I think that a quant trader would write code to manage their investment from begin to end. It’s a simple, practical approach that can be programmed to:
- Find stocks based on requirements of their investment style
- Filter stocks by some more criteria
- Filter more
- List of potential stocks
- From there one could select which stock would be in the portfolio
- Track buy / sell history
- Predict market to see profit / loss
- Predict / Simulate often
- Make decision
- Repeat from the tracking above
Those algorithms are basic calculations and filtering. You only need to know what are you looking for and implement it. The most difficult part is how to analyze and form your way of investing.