The complexity of an expression is defined by the number of && and || operators it contains.
A single expression’s complexity should not become too high to keep the code readable.
Noncompliant code example
With the default threshold value of 3:
if (((condition1 && condition2) || (condition3 && condition4)) && condition5) { ... }
Compliant solution
if ((myFirstCondition || mySecondCondition) && myLastCondition) { ... }
