porterskyandQwen 3.8 27B
a65e84e796
Extend the Ex42 observer pattern with Hint objects so each observer receives the reason for the update instead of querying the subject: - Subject::notify() and Observer::update() now take a const Hint& argument. - Add LightHint and WaitHint carrying the traffic light state and WAIT button state, defined in Pelican.h. - Pole dispatches on hint type using dynamic_cast. - The Pole constructor sets its initial lights directly from the Pelican's current state, since no notification is sent at startup. Stopgap until the initial update is handled properly. Co-authored-by: Qwen 3.8 27B <qwen3.8_27b-q3_k_xl@lmstudio.local>
64 lines
1.4 KiB
C++
64 lines
1.4 KiB
C++
// ======================================================
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//
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// Represents a Pelican crossing
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//
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// ======================================================
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#ifndef PELICAN_H
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#define PELICAN_H
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#include "Subject.h"
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class PelicanTimer;
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class Pelican : public Subject {
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public:
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Pelican();
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// call when the WAIT button has been pressed
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void press(void);
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// states that a Pelican can be in
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enum PelicanState { RED_STATE, YELLOW_FLASHING, GREEN_TIMING, GREEN_IDLE, YELLOW_STATE };
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bool isPressed() const { return pressed; }
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PelicanState getState() const { return state; }
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private:
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// state that this Pelican is in
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PelicanState state;
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// called by PelicanTimer when the lights need to change
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void timerExpired(void);
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const unsigned int RED_TIME;
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const unsigned int YELLOW_TIME;
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const unsigned int GREEN_TIME;
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const unsigned int FLASH_TIME;
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// indicates whether the WAIT light should be on
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bool pressed;
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// Timer that indicates when the lights should change
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PelicanTimer *myTimer;
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private:
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// prevent general use of copy ctor and operator=
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Pelican(const Pelican &);
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Pelican &operator=(const Pelican &);
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};
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class LightHint : public Hint {
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public:
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LightHint(Pelican::PelicanState s) : state(s) { }
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Pelican::PelicanState state;
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};
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class WaitHint : public Hint {
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public:
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WaitHint (bool p) : pressed(p) {}
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bool pressed;
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};
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#endif
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