Constructive res judicata is contained in Explanation IV to Section 11 CPC. It provides that any matter which might and ought to have been raised as a ground of attack or defense in the former suit shall be deemed to have been directly in issue — even if not actually raised.

1. 1 Pick up CPC.
2. 2 Go to Section 11 — Res Judicata.
3. 3 Read Explanation IV: constructive res judicata — matters that could have been raised are deemed raised.