Answer
Covariance allows using derived types where base types are expected. Contravariance allows the opposite.
They enable flexible delegate and interface usage.
Quick Answer
Covariance (out T on interfaces like IEnumerable) lets you use a more derived type where a base is expected — safe for read-only scenarios. Contravariance (in T on Action) lets you use a more base type — safe for write-only scenarios. Applies to interfaces and delegates, not classes.
S
SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ