According to me, you should understand at least the following metrics at beginning:
Lack of cohesion of methods (LCOM) is a measure of the number of responsabilities of class.
Thus, if you consider the SOLID principles, the ideal LCOM is
We can take an example:
If we examine this class, we get two flows:
Therefore, the LCOM value for
Example has two responsabilities.
Maintainability index evaluates ... the maintainability of any project. It provides a score between 0 to 221.
This score is standard, and works for any language :
The calculation's formula is the one created in 1992 by Paul Oman and Jack Hagemeister, promoted by the Software Engine Institute (SEI) in 1997:
MI = 171 - 5.2 * log2(V) - 0.23 * CC - 16.2 * log2 (LOC) + 50 * sin (sqrt(2.4 * CM))