finished seminar04

seminar04_templates/08_ref/main.cpp

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+#include <iostream>
+#include <string>
+#include <vector>
+
+using std::cout, std::endl, std::string, std::vector;
+
+template <typename T>
+class Ref {
+private:
+        T* mPtr;
+public:
+        Ref(T& t) {
+            mPtr = &t;
+        }
+        Ref(Ref& t) {
+            mPtr = t.mPtr;
+        }
+        Ref() {
+            mPtr = nullptr;
+        }
+        T& get() {
+            return *mPtr;
+        }
+        T operator=(const T& t) {
+            new(mPtr) T{t};
+            return *mPtr;
+        }
+        T operator+(const T& t) {
+            return *mPtr + t;
+        } 
+        T operator+=(const T& t) {
+            *mPtr = *mPtr + t;
+            return *mPtr;
+        }
+        T* operator->() {
+            return mPtr;
+        }
+        template <typename U>
+        friend std::ostream& operator<<(std::ostream& out, Ref<U> r);
+};
+
+template <typename T>
+std::ostream& operator<<(std::ostream& out, Ref<T> r) {
+    out << *(r.mPtr);
+    return out;
+}
+
+void toUpper(Ref<string> r) {
+    for(size_t i = 0; i < r->size(); ++i)
+        r.get()[i] = toupper(r.get()[i]); 
+}
+
+int main() {
+    int a = 10;
+    Ref<int> ra = a;
+    cout << ra << endl;
+
+    string s = "Cat";
+    Ref<string> rs = s;
+    rs = "Mouse";
+    rs += "Elephant";
+    cout << rs << endl;
+    cout << s << endl;
+
+    toUpper(s);
+    cout << s << endl;
+
+    vector<string> animals {"Cat", "Dogs", "Elephants", "Worms"};
+    vector<Ref<string>> refs {animals.begin(), animals.end()};
+
+    for (int i = 0; i < refs.size(); ++i)
+            cout << animals[i] << " ";
+    cout << endl;
+}