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  1. #include <iostream>
  2. #include <vector>
  3. #include <functional>
  4. #include <algorithm>
  5.  
  6. using namespace std;
  7.  
  8. #define FORWARD_ASSIGN(from, to) \
  9.     from(to const& other) : to(other) {} \
  10.     from const& operator=(from const& other) { to::operator=(other); return *this; }
  11.  
  12. #define FORWARD_ARITHMETIC_OPS(from, to) \
  13.     from& operator+=(from const& other) { \
  14.         to::operator+=(other); return *this; \
  15.     } \
  16.     from& operator-=(from const& other) { \
  17.         to::operator-=(other); return *this; \
  18.     } \
  19.     from& operator*=(from const& other) { \
  20.         to::operator*=(other); return *this; \
  21.     } \
  22.     from& operator/=(from const& other) { \
  23.         to::operator/=(other); return *this; \
  24.     } \
  25.     friend from operator+(from const& lhs, from const& rhs) { \
  26.         return operator+(lhs.operator to(), rhs.operator to()); \
  27.     } \
  28.     friend from operator-(from const& lhs, from const& rhs) { \
  29.         return operator-(lhs.operator to(), rhs.operator to()); \
  30.     } \
  31.     friend from operator*(from const& lhs, from const& rhs) { \
  32.         return operator*(lhs.operator to(), rhs.operator to()); \
  33.     } \
  34.     friend from operator/(from const& lhs, from const& rhs) { \
  35.         return operator/(lhs.operator to(), rhs.operator to()); \
  36.     }
  37.  
  38. //folgendes wäre Teil der Standardlibrary
  39. //nur minimale features implementiert (zeitgründe)
  40. class Integer {
  41. public:
  42.     typedef int BaseType;
  43.     int value;
  44.  
  45.     Integer(int value=0) : value(value) {}
  46.     Integer(Integer const& other) : value(other.value) {}
  47.  
  48.     Integer& operator=(Integer const& other) {
  49.         value=other.value;
  50.         return *this;
  51.     }
  52.  
  53.     Integer& operator+=(Integer const& other) {
  54.         value+=other.value;
  55.         return *this;
  56.     }
  57.     Integer& operator-=(Integer const& other) {
  58.         value-=other.value;
  59.         return *this;
  60.     }
  61.     Integer& operator*=(Integer const& other) {
  62.         value*=other.value;
  63.         return *this;
  64.     }
  65.     Integer& operator/=(Integer const& other) {
  66.         value/=other.value;
  67.         return *this;
  68.     }
  69.  
  70. };
  71.  
  72. Integer operator+(Integer const& lhs, Integer const& rhs) {
  73.     return Integer(lhs.value+rhs.value);
  74. }
  75. Integer operator-(Integer const& lhs, Integer const& rhs) {
  76.     return Integer(lhs.value-rhs.value);
  77. }
  78. Integer operator*(Integer const& lhs, Integer const& rhs) {
  79.     return Integer(lhs.value*rhs.value);
  80. }
  81. Integer operator/(Integer const& lhs, Integer const& rhs) {
  82.     return Integer(lhs.value/rhs.value);
  83. }
  84.  
  85.  
  86. class PositiveInteger : protected Integer {
  87. public:
  88.     typedef int BaseType;
  89.  
  90.     PositiveInteger(int value=0) : Integer(value) { if(value<0) throw "Negative Value"; }
  91.     PositiveInteger(Integer const& other) : Integer(other) { if(value<0) throw "Negative Value"; }
  92.  
  93.     PositiveInteger& operator=(Integer const& other) {
  94.         if(other.value < 0) throw "Negative Value";
  95.         value=other.value;
  96.         return *this;
  97.     }
  98.  
  99.     operator Integer() const { return *this; }
  100.     FORWARD_ARITHMETIC_OPS(PositiveInteger, Integer)
  101. };
  102.  
  103.  
  104.  
  105.  
  106. template<typename T>
  107. class Vector {
  108. private:
  109.     vector<T> impl;
  110.  
  111. public:
  112.     void add(T const& val) {
  113.         impl.push_back(val);
  114.     }
  115.  
  116.     template<typename F>
  117.     void for_each(F f) {
  118.         for(auto& obj : impl) {
  119.             f(obj);
  120.         }
  121.     }
  122. };
  123.  
  124. template<typename T>
  125. class ChangeObserver : public Vector<function<void(T const&, T const&)> > {
  126. public:
  127.     void change(T const& oldVal, T const& newVal) {
  128.         this->for_each([&](function<void(T const&, T const&)> f) { f(oldVal, newVal); });
  129.     }
  130. };
  131.  
  132. template<typename ValueType>
  133. class ChangeObservableArithmeticType : protected ValueType, public ChangeObserver<ValueType> {
  134. public:
  135.     typedef typename ValueType::BaseType BaseType;
  136.     ChangeObservableArithmeticType(typename ValueType::BaseType value=0) : ValueType(value) {}
  137.     ChangeObservableArithmeticType(ChangeObservableArithmeticType const& other) : ValueType(other) {}
  138.     ChangeObservableArithmeticType(ValueType const& other) : ValueType(other) {}
  139.  
  140.     ChangeObservableArithmeticType& operator=(ChangeObservableArithmeticType const& other) {
  141.         this->change(*this, other);
  142.         this->value=other.value;
  143.         return *this;
  144.     }
  145.  
  146.     operator ValueType() const {
  147.         return *this;
  148.     }
  149.  
  150.     FORWARD_ARITHMETIC_OPS(ChangeObservableArithmeticType, ValueType)
  151. };
  152.  
  153.  
  154.  
  155. class Radius : public ChangeObservableArithmeticType<PositiveInteger> {
  156. public:
  157.     Radius() {}
  158.     Radius(ChangeObservableArithmeticType::BaseType value) : ChangeObservableArithmeticType(value) {}
  159.     PositiveInteger const& asPositiveInteger() const {
  160.         return *this;
  161.     }
  162.  
  163.     FORWARD_ASSIGN(Radius, ChangeObservableArithmeticType)
  164. };
  165.  
  166. class Punkt : public Integer {
  167. public:
  168.     FORWARD_ASSIGN(Punkt, Integer)
  169.     Punkt(int val) : Integer(val) {}
  170. };
  171.  
  172. class PunktX : public Punkt { public: FORWARD_ASSIGN(PunktX, Punkt) PunktX(int val):Punkt(val){} };
  173. class PunktY : public Punkt { public: FORWARD_ASSIGN(PunktY, Punkt) PunktY(int val):Punkt(val){} };
  174.  
  175. class PunktXY : public PunktX, public PunktY {
  176. public:
  177.     PunktXY(int x=0, int y=0) : PunktX(x), PunktY(y) {}
  178. };
  179.  
  180. class Startpunkt : public PunktXY { public: FORWARD_ASSIGN(Startpunkt, PunktXY) };
  181. class Endpunkt : public PunktXY { public: FORWARD_ASSIGN(Endpunkt, PunktXY) };
  182.  
  183. class Kreis : public Radius, public PunktXY {
  184. public:
  185.     Kreis(int r) : Radius(r) {
  186.         Radius::add([&](::PositiveInteger const&, ::PositiveInteger const&) {
  187.             redraw();
  188.         });
  189.  
  190.         redraw();
  191.     }
  192.  
  193.     void redraw() {
  194.         cout<<"Radius changed, Kreis redrawn\n";
  195.     }
  196. };
  197.  
  198. class Laenge : public Integer { public: FORWARD_ASSIGN(Laenge, Integer) };
  199.  
  200. class Strecke : public Startpunkt, public Endpunkt {
  201. public:
  202.     Strecke() : Startpunkt(PunktXY(0,0)), Endpunkt(PunktXY(0,0)) {}
  203. };
  204.  
  205. class Rechteck : public PunktXY, public Laenge {
  206. public:
  207.     Rechteck(int laenge) : Laenge(laenge) {}
  208. };
  209.  
  210. void verdoppleRadius(Radius& r) {
  211.     r=r*2;
  212. }
  213.  
  214. void printKoordinaten(PunktXY const& p) {
  215.     cout<<"("<<p.PunktX::value<<"/"<<p.PunktY::value<<")\n";
  216. }
  217.  
  218. void wierdShit(Kreis& k, Laenge& l) {
  219.     l=l*static_cast<PunktX&>(k)+static_cast<PunktY&>(k);
  220. }
  221.  
  222. int main() {
  223.  
  224.     Kreis k(3);
  225.     Rechteck r(12);
  226.     Strecke s;
  227.  
  228.     k.PunktXY::operator=(PunktXY(10,20));
  229.     r.PunktXY::operator=(PunktXY(1,2));
  230.     s.Startpunkt::operator=(PunktXY(5,7));
  231.     s.Endpunkt::operator=(PunktXY(15,17));
  232.  
  233.     //2x redraw ausführen:
  234.     k.Radius::operator=(7);
  235.  
  236.     try {
  237.         //force error
  238.         k.Radius::operator=(-7);
  239.     } catch(...) {
  240.         cout<<"Error\n";
  241.     }
  242.  
  243.     verdoppleRadius(k);
  244.  
  245.     printKoordinaten(k);
  246.     printKoordinaten(r);
  247.     printKoordinaten(static_cast<Startpunkt&>(s));
  248.  
  249.  
  250.  
  251.     return 0;
  252. }
  253.  
  254.  
Success #stdin #stdout 0s 2988KB
comments (?)
stdin 
Standard input is empty
stdout 
Radius changed, Kreis redrawn
Radius changed, Kreis redrawn
Error
Radius changed, Kreis redrawn
(10/20)
(1/2)
(5/7)
https://ideone.com/5YY8an
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
secret

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