chore: Add course material

397/Ex51/Ex51.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 2013
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+MinimumVisualStudioVersion = 10.0.40219.1
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+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Win32 = Debug|Win32
+		Release|Win32 = Release|Win32
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{AFB7826A-449B-436C-A7FC-4401601F082B}.Debug|Win32.ActiveCfg = Debug|Win32
+		{AFB7826A-449B-436C-A7FC-4401601F082B}.Debug|Win32.Build.0 = Debug|Win32
+		{AFB7826A-449B-436C-A7FC-4401601F082B}.Release|Win32.ActiveCfg = Release|Win32
+		{AFB7826A-449B-436C-A7FC-4401601F082B}.Release|Win32.Build.0 = Release|Win32
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal

397/Ex51/Ex51.vcxproj

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+    <Link>
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+  <ItemGroup>
+    <ClCompile Include="..\DOS_Unix\Keyboard_DOS.cpp" />
+    <ClCompile Include="..\DOS_Unix\Screen_DOS.cpp" />
+    <ClCompile Include="Light.cpp" />
+    <ClCompile Include="main.cpp" />
+    <ClCompile Include="Pelican.cpp" />
+    <ClCompile Include="PelicanTimer.cpp" />
+    <ClCompile Include="Pole.cpp" />
+    <ClCompile Include="Subject.cpp" />
+    <ClCompile Include="Timer.cpp" />
+    <ClCompile Include="TimerSet.cpp" />
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+    <ClInclude Include="Pelican.h" />
+    <ClInclude Include="PelicanTimer.h" />
+    <ClInclude Include="Pole.h" />
+    <ClInclude Include="Subject.h" />
+    <ClInclude Include="Timer.h" />
+    <ClInclude Include="TimerSet.h" />
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+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
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397/Ex51/Ex51.vcxproj.filters

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397/Ex51/Ex51.vcxproj.user

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+  <PropertyGroup />
+</Project>

397/Ex51/Light.cpp

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+
+
+#include "Light.h"
+#include "Pelican.h"
+#include "Screen.h"
+#include <iostream>
+
+Light::Light(std::string name, int x, int y, int color) : x(x), y(y), c(color), name(name) {}
+
+Light::~Light() {
+    std::cout << "Deleting light (" << name << ", " << x << ", " << y << ", " << c << ")"
+              << "\n";
+}
+
+void Light::set(LightState newState) {
+    state = newState;
+    Screen::write(name.c_str(), x, y, state == FLASH ? (128 + c) : (state == OFF ? 0 : c));
+    // 128 + color was used to make a character flash (but not any more)
+}
+
+Light::LightState Light::get(void) { return state; }

397/Ex51/Light.h

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+// ======================================================
+//
+// Represents a light, implemented as a string written
+// to a console window
+//
+// ======================================================
+
+#ifndef LIGHT_H
+#define LIGHT_H
+
+#include <string>
+
+class Light {
+  public:
+    Light(std::string name, int x, int y, int color);
+    ~Light();
+
+    enum LightState { ON, OFF, FLASH };
+
+    void set(LightState new_state);
+    LightState get(void);
+
+  private:
+    int c; // light colour
+    int x, y;
+    std::string name;
+    LightState state;
+};
+
+#endif

397/Ex51/Observer.h

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+
+#ifndef OBSERVER_H
+#define OBSERVER_H
+
+#include "Subject.h"
+
+class Observer {
+  public:
+    virtual void update(const Hint &) = 0;
+};
+
+#endif

397/Ex51/Pelican.cpp

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+
+#include "Pelican.h"
+#include "PelicanTimer.h"
+#include "Pole.h"
+
+Pelican::Pelican() : pressed(false), RED_TIME(4), YELLOW_TIME(2), GREEN_TIME(3), FLASH_TIME(5), state(GREEN_IDLE) {
+    myTimer = new PelicanTimer(*this, &Pelican::timerExpired);
+}
+
+void Pelican::press(void) {
+    if (state == GREEN_IDLE) {
+        state = YELLOW_STATE;
+        myTimer->timeoutRequest(YELLOW_TIME);
+        pressed = true;
+
+        notify(WaitHint(pressed));
+        notify(LightHint(state));
+    } else if (state != RED_STATE) {
+        pressed = true;
+        notify(WaitHint(pressed));
+    }
+}
+
+void Pelican::timerExpired(void) {
+    switch (state) {
+    case RED_STATE:
+        state = YELLOW_FLASHING;
+        myTimer->timeoutRequest(FLASH_TIME);
+        break;
+
+    case YELLOW_FLASHING:
+        state = GREEN_TIMING;
+        myTimer->timeoutRequest(GREEN_TIME);
+        break;
+
+    case GREEN_TIMING:
+        if (pressed) {
+            state = YELLOW_STATE;
+            myTimer->timeoutRequest(YELLOW_TIME);
+        } else {
+            state = GREEN_IDLE;
+        }
+        break;
+
+    case GREEN_IDLE:
+        //    should never happen
+        break;
+
+    case YELLOW_STATE:
+        state = RED_STATE;
+        pressed = false;
+        notify(WaitHint(pressed));
+        myTimer->timeoutRequest(RED_TIME);
+        break;
+    }
+
+    notify(LightHint(state));
+}

397/Ex51/Pelican.h

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+// ======================================================
+//
+// Represents a Pelican crossing
+//
+// ======================================================
+
+#ifndef PELICAN_H
+#define PELICAN_H
+
+#include "Subject.h"
+
+class PelicanTimer;
+
+class Pelican : public Subject {
+  public:
+    Pelican();
+
+    // call when the WAIT button has been pressed
+    void press(void);
+
+    // states that a Pelican can be in
+    enum PelicanState { RED_STATE, YELLOW_FLASHING, GREEN_TIMING, GREEN_IDLE, YELLOW_STATE };
+
+    bool isPressed() const { return pressed; }
+    PelicanState getState() const { return state; }
+
+  private:
+    // state that this Pelican is in
+    PelicanState state;
+
+    // called by PeleicanTimer when the lights need to change
+    void timerExpired(void);
+
+    const unsigned int RED_TIME;
+    const unsigned int YELLOW_TIME;
+    const unsigned int GREEN_TIME;
+    const unsigned int FLASH_TIME;
+
+    // indicates whether the WAIT light should be on
+    bool pressed;
+
+    // Timer that indicates when the lights should change
+    PelicanTimer *myTimer;
+
+  private:
+    //  prevent general use of copy ctor and operator=
+    Pelican(const Pelican &);
+    Pelican &operator=(const Pelican &);
+};
+
+class LightHint : public Hint {
+  public:
+    LightHint(Pelican::PelicanState s) : state(s) {}
+
+    Pelican::PelicanState state;
+};
+
+class WaitHint : public Hint {
+  public:
+    WaitHint(bool p) : pressed(p) {}
+
+    bool pressed;
+};
+
+#endif

397/Ex51/PelicanTimer.cpp

@@ -0,0 +1,7 @@
+
+
+#include "PelicanTimer.h"
+
+PelicanTimer::PelicanTimer(Pelican &target, TargetFunc targetFunc) : myTarget(target), myTargetFunc(targetFunc) {}
+
+void PelicanTimer::doExpired() { (myTarget.*myTargetFunc)(); }

397/Ex51/PelicanTimer.h

@@ -0,0 +1,27 @@
+// ======================================================
+//
+// This class specializes the Timer to enable it to
+// stimulate a Pelican
+//
+// ======================================================
+
+#ifndef PelicanTimer_H
+#define PelicanTimer_H
+
+#include "Pelican.h"
+#include "Timer.h"
+
+class PelicanTimer : public Timer {
+  public:
+    typedef void (Pelican::*TargetFunc)();
+
+    PelicanTimer(Pelican &target, TargetFunc targetFunc);
+
+  private:
+    void doExpired();
+
+    Pelican &myTarget;
+    TargetFunc myTargetFunc;
+};
+
+#endif

397/Ex51/Pole.cpp

@@ -0,0 +1,78 @@
+#include "Pole.h"
+#include "Screen.h"
+
+Pole::Pole(int x, int y, Pelican &p) : waitLight(new Light("WAIT", x + 6, y + 12, Screen::WHITE)), myPelican(p) {
+    myPelican.attach(*this);
+
+    using namespace Screen; // we will discuss namespaces in the course
+
+    lights[RED_LIGHT] = new Light("*", x + 11, y + 3, RED);
+    lights[RED_MAN] = new Light("*<-=", x + 6, y + 4, RED);
+    lights[YELLOW_LIGHT] = new Light("*", x + 11, y + 5, YELLOW);
+    lights[GREEN_LIGHT] = new Light("*", x + 11, y + 7, GREEN);
+    lights[GREEN_MAN] = new Light("*|-<", x + 6, y + 7, GREEN);
+
+    write("       _____         ", x, ++y, GRAY);
+    write("      /___ /|        ", x, ++y, GRAY);
+    write("     |    | |        ", x, ++y, GRAY);
+    write("     |    |/|        ", x, ++y, GRAY);
+    write("     |____| |        ", x, ++y, GRAY);
+    write("     |    |/|        ", x, ++y, GRAY);
+    write("     |    | |        ", x, ++y, GRAY);
+    write("     |____|/         ", x, ++y, GRAY);
+    write("       _||__         ", x, ++y, GRAY);
+    write("      /___ /|        ", x, ++y, GRAY);
+    write("     |    | |        ", x, ++y, GRAY);
+    write("     |    | |        ", x, ++y, GRAY);
+    write("     |____|/         ", x, ++y, GRAY);
+    write("        ||           ", x, ++y, GRAY);
+    write("        ||           ", x, ++y, GRAY);
+    write("        ||           ", x, ++y, GRAY);
+    write("        ||           ", x, ++y, GRAY);
+    write("        ||           ", x, ++y, GRAY);
+    write("        ||           ", x, ++y, GRAY);
+    write("========||===========", x, ++y, GRAY);
+    write("    /   ||     /     ", x, ++y, GRAY);
+    write("_ /_________ /_      ", x, ++y, GRAY);
+    write("/          /         ", x, ++y, GRAY);
+
+    update(Hint());
+}
+
+Pole::~Pole() {
+    for (int i = 0; i < sizeof lights / sizeof(lights[0]); ++i)
+        delete lights[i];
+    delete waitLight;
+}
+
+void Pole::setTrafficLights(Pelican::PelicanState state) {
+    static const Light::LightState LightStates[Pelican::YELLOW_STATE + 1][RED_MAN + 1] = {
+        //  red         yellow        green       green man     red man
+        {Light::ON, Light::OFF, Light::OFF, Light::ON, Light::OFF},       // red
+        {Light::OFF, Light::FLASH, Light::OFF, Light::FLASH, Light::OFF}, // y flash
+        {Light::OFF, Light::OFF, Light::ON, Light::OFF, Light::ON},       // g time
+        {Light::OFF, Light::OFF, Light::ON, Light::OFF, Light::ON},       // g idle
+        {Light::OFF, Light::ON, Light::OFF, Light::OFF, Light::ON}        // yellow
+    };
+
+    for (int i = RED_LIGHT; i <= RED_MAN; i++) {
+        lights[i]->set(LightStates[state][i]);
+    }
+}
+
+void Pole::setWaitLight(bool pressed) { waitLight->set(pressed ? Light::ON : Light::OFF); }
+
+void Pole::update(const Hint &h) {
+    const WaitHint *waitHintPtr;
+    const LightHint *lightHintPtr;
+
+    if ((waitHintPtr = dynamic_cast<const WaitHint *>(&h)) != 0) {
+        setWaitLight(waitHintPtr->pressed);
+    } else if ((lightHintPtr = dynamic_cast<const LightHint *>(&h)) != 0) {
+        setTrafficLights(lightHintPtr->state);
+    } else {
+        // don't know what's changed, so update everything
+        setTrafficLights(myPelican.getState());
+        setWaitLight(myPelican.isPressed());
+    }
+}

397/Ex51/Pole.h

@@ -0,0 +1,28 @@
+
+#ifndef POLE_H
+#define POLE_H
+
+#include "Light.h"
+#include "Observer.h"
+#include "Pelican.h"
+
+class Pole : public Observer {
+  public:
+    Pole(int x, int y, Pelican &p);
+    ~Pole();
+
+    void setTrafficLights(Pelican::PelicanState state);
+    void setWaitLight(bool pressed);
+
+    void update(const Hint &);
+
+  private:
+    Pelican &myPelican;
+
+    enum LightName { RED_LIGHT, YELLOW_LIGHT, GREEN_LIGHT, GREEN_MAN, RED_MAN };
+
+    Light *lights[RED_MAN + 1];
+    Light *waitLight;
+};
+
+#endif

397/Ex51/Subject.cpp

@@ -0,0 +1,12 @@
+
+
+#include "Subject.h"
+#include "Observer.h"
+
+void Subject::attach(Observer &obs) { myObservers.insert(&obs); }
+
+void Subject::notify(const Hint &h) const {
+    for (ObsList::const_iterator iter = myObservers.begin(); iter != myObservers.end(); ++iter) {
+        (*iter)->update(h);
+    }
+}

397/Ex51/Subject.h

@@ -0,0 +1,26 @@
+
+#ifndef SUBJECT_H
+#define SUBJECT_H
+
+class Observer;
+
+#include <set>
+
+class Hint {
+  public:
+    virtual ~Hint() {}
+};
+
+class Subject {
+  public:
+    typedef std::set<Observer *> ObsList;
+    void attach(Observer &obs);
+
+  protected:
+    void notify(const Hint &) const;
+
+  private:
+    ObsList myObservers;
+};
+
+#endif

397/Ex51/Timer.cpp

@@ -0,0 +1,23 @@
+
+
+#include "Timer.h"
+#include "TimerSet.h"
+
+void Timer::timeoutRequest(int seconds) { timeToGo = seconds; }
+
+Timer::Timer() : timeToGo(-1) { TimerSet::Instance().addATimer(this); }
+
+void Timer::tick() {
+    if (isExpired()) {
+        doExpired();
+    }
+}
+
+bool Timer::isExpired() {
+    if (timeToGo > 0) {
+        if (--timeToGo == 0) {
+            return true;
+        }
+    }
+    return false;
+}

397/Ex51/Timer.h

@@ -0,0 +1,32 @@
+// ======================================================
+//
+// A general-purpose countdown timer
+// To use this class, specialize it
+// and override tick()
+//
+// ======================================================
+
+#ifndef timer_H
+#define timer_H
+
+#include <ctime>
+
+class Timer {
+  public:
+    Timer();
+
+    void timeoutRequest(int seconds);
+
+    // template method
+    void tick();
+
+  protected:
+    bool isExpired();
+
+  private:
+    virtual void doExpired() = 0;
+
+    int timeToGo;
+};
+
+#endif

397/Ex51/TimerSet.cpp

@@ -0,0 +1,24 @@
+#include "TimerSet.h"
+#include "Timer.h"
+#include <iostream>
+
+TimerSet::TimerSet() : previousTime(time(NULL)) {}
+
+void TimerSet::addATimer(Timer *t) { timers.push_back(t); }
+
+void TimerSet::pollAllTimers() {
+    std::time_t timeNow;
+    if (time(&timeNow) > previousTime) {
+        previousTime = timeNow;
+
+        for (auto it = timers.begin(); it != timers.end(); it++) {
+            (*it)->tick();
+        }
+    }
+}
+
+TimerSet &TimerSet::Instance() {
+    // Meyer's Singleton implementation
+    static TimerSet pInstance;
+    return pInstance;
+}

397/Ex51/TimerSet.h

@@ -0,0 +1,29 @@
+#ifndef TIMERSET_H
+#define TIMERSET_H
+
+#include <ctime>
+#include <vector>
+
+class Timer;
+
+class TimerSet {
+  public:
+    void pollAllTimers();
+    void addATimer(Timer *);
+
+  private:
+    TimerSet();
+    std::vector<Timer *> timers;
+    std::time_t previousTime;
+
+    //  Meyer's singleton
+  public:
+    static TimerSet &Instance();
+
+  private:
+    // prevent copying and assignment of the singleton
+    TimerSet(const TimerSet &);
+    TimerSet &operator=(const TimerSet &);
+};
+
+#endif

397/Ex51/main.cpp

@@ -0,0 +1,32 @@
+
+
+#include "Keyboard.h"
+#include "Pelican.h"
+#include "Pole.h"
+#include "TimerSet.h"
+
+#include <cctype> // provides toupper()
+
+int main() {
+    Keyboard kbd;
+    Pelican thePelican;
+    Pole pole1(20, 0, thePelican);
+    Pole pole2(40, 0, thePelican);
+
+    char c = 0;
+
+    while (std::toupper(c) != 'Q') { // loop until 'Q' is pressed
+
+        while (!kbd.isCharAvail()) {
+            TimerSet::Instance().pollAllTimers(); // no key press to process, poll the timers
+        }
+
+        c = kbd.getChar(); // get the character
+        if (c == ' ') {
+            // it's a space, so press the WAIT button
+            thePelican.press();
+        }
+    }
+
+    return 0;
+}