You must read the code and be the processor and follow it step by step what it does. Use pencil and paper to write down the state of variables.
Although it may sounds stupid at first you will see through the eyes of the processor and learn a lot 
You must read the code and be the processor and follow it step by step what it does. Use pencil and paper to write down the state of variables.
Although it may sounds stupid at first you will see through the eyes of the processor and learn a lot