How does Strategy pattern differ from State pattern?

Aspect Strategy Pattern State Pattern

Purpose Encapsulates interchangeable

behaviors (algorithms).

Encapsulates states and transitions

between them.

Client

Control

Client decides which strategy to use. Object changes its own state

internally.

Behavior

Switch

Switched externally (e.g., passed as

a parameter).

Switched internally (e.g., via

method call).

Example Payment method selection. Document lifecycle (Draft →

Published → Archived).

Repository Design Pattern