🔧 Adding

Strategy Design Pattern

Author: raj713335

06 Behavioral Design Patterns/08 Strategy Design Pattern.py

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+from abc import ABC, abstractmethod
+
+
+# ----------- STRATEGY INTERFACE -----------
+class RouteStrategy(ABC):
+    @abstractmethod
+    def build_route(self, start: str, end: str) -> None:
+        ...
+
+
+# ----------- CONCRETE STRATEGIES -----------
+class DrivingStrategy(RouteStrategy):
+    def build_route(self, start: str, end: str) -> None:
+        print(f"🚗 Calculating driving route from {start} to {end} via highways and roads.")
+
+
+class WalkingStrategy(RouteStrategy):
+    def build_route(self, start: str, end: str) -> None:
+        print(f"🚶 Calculating walking route from {start} to {end} via pedestrian paths.")
+
+
+class PublicTransportStrategy(RouteStrategy):
+    def build_route(self, start: str, end: str) -> None:
+        print(f"🚌 Calculating public transport route from {start} to {end} using bus/train schedules.")
+
+
+# ----------- CONTEXT -----------
+class Navigator:
+    def __init__(self, strategy: RouteStrategy):
+        self._strategy = strategy
+
+    def set_strategy(self, strategy: RouteStrategy) -> None:
+        self._strategy = strategy
+        print(f"[Navigator] Strategy changed to: {strategy.__class__.__name__}")
+
+    def navigate(self, start: str, end: str) -> None:
+        print(f"[Navigator] Routing from {start} to {end}...")
+        self._strategy.build_route(start, end)
+
+
+# ----------- CLIENT CODE -----------
+def main():
+    # Create context with a default strategy
+    navigator = Navigator(DrivingStrategy())
+
+    # Simulate user selecting different modes
+    navigator.navigate("Central Park", "Empire State Building")
+
+    navigator.set_strategy(WalkingStrategy())
+    navigator.navigate("Central Park", "Empire State Building")
+
+    navigator.set_strategy(PublicTransportStrategy())
+    navigator.navigate("Central Park", "Empire State Building")
+
+
+if __name__ == "__main__":
+    main()