Frankly speaking, it mainly considers from the features of analog computer and digital computer.
Analog computer: The computer inputs analog signal whose numerical value is represented by continuous quantity and the operation process is continuous; However, analog signal is awful precision, slow speed and terrible anti-interference in dealing with problems;
Digital computer: The numerical value is shown via digital quantity and the operation is processed as bit.
In a nutshell, compared to analog computer, digital computer is much better in terms of composition structure and performance.