feat(Week11): Add solutions HEAD main

2 files changed, 146 insertions, 0 deletions

diff --git a/Week11/Exercise03/SharedPointer.hpp b/Week11/Exercise03/SharedPointer.hpp
new file mode 100644
index 0000000..06f9bbb
--- /dev/null
+++ b/Week11/Exercise03/SharedPointer.hpp
@@ -0,0 +1,129 @@
+#ifndef _SHAREDPOINTER
+#define _SHAREDPOINTER
+
+template<class T>
+class SharedPointer {
+	T* value;
+	unsigned* instances;
+
+	void free();
+	void copyFrom(const SharedPointer& other);
+
+public:
+	SharedPointer(T* value);
+
+	SharedPointer();
+	~SharedPointer();
+	SharedPointer(const SharedPointer& other);
+	SharedPointer& operator=(const SharedPointer& other);
+
+	SharedPointer(SharedPointer&& other);
+	SharedPointer& operator=(SharedPointer&& other);
+
+	T& operator*();
+	const T& operator*() const;
+	T* operator->();
+	const T* operator->() const;
+
+	unsigned RefCount() const;
+};
+
+template <class T>
+void SharedPointer<T>::free() {
+	if (instances == nullptr)
+		return;
+
+	--*instances;
+	if (*instances == 0) {
+		delete instances;
+		delete value;
+	}
+}
+
+template <class T>
+void SharedPointer<T>::copyFrom(const SharedPointer& other) {
+	this->instances = other.instances;
+	this->value = other.value;
+	++*instances;
+}
+
+template <class T>
+SharedPointer<T>::SharedPointer(T* value) : instances(new unsigned), value(value)
+{
+	*instances = 1;
+}
+
+template <class T>
+SharedPointer<T>::SharedPointer() : instances(), value()
+{ }
+
+template <class T>
+SharedPointer<T>::~SharedPointer() {
+	free();
+}
+
+template <class T>
+SharedPointer<T>::SharedPointer(const SharedPointer& other) {
+	copyFrom(other);
+}
+
+template <class T>
+SharedPointer<T>& SharedPointer<T>::operator=(const SharedPointer& other) {
+	if (this != &other) {
+		free();
+		copyFrom(other);
+	}
+	return *this;
+}
+
+template <class T>
+SharedPointer<T>::SharedPointer(SharedPointer&& other) {
+	instances = other.instances;
+	value = other.value;
+
+	other.instances = nullptr;
+	other.value = nullptr;
+}
+
+template <class T>
+SharedPointer<T>& SharedPointer<T>::operator=(SharedPointer&& other) {
+	if (this != &other) {
+		free();
+
+		instances = other.instances;
+		value = other.value;
+
+		other.instances = nullptr;
+		other.value = nullptr;
+	}
+	return *this;
+}
+
+template <class T>
+T& SharedPointer<T>::operator*() {
+	return *value;
+}
+
+template <class T>
+const T& SharedPointer<T>::operator*() const {
+	return *value;
+}
+
+template <class T>
+T* SharedPointer<T>::operator->() {
+	return value;
+}
+
+template <class T>
+const T* SharedPointer<T>::operator->() const {
+	return value;
+}
+
+template <class T>
+unsigned SharedPointer<T>::RefCount() const {
+	if (instances == nullptr)
+		return 0;
+	return *instances;
+}
+
+#endif /* _SHAREDPOINTER */
diff --git a/Week11/Exercise03/main.cpp b/Week11/Exercise03/main.cpp
new file mode 100644
index 0000000..d8a4d66
--- /dev/null
+++ b/Week11/Exercise03/main.cpp
@@ -0,0 +1,17 @@
+#include "SharedPointer.hpp"
+#include <iostream>
+
+void inc(SharedPointer<int> val) {
+	(*val)++;
+}
+
+int main() {
+	SharedPointer<int> x(new int);
+	SharedPointer<int> y = x;
+	*x = 5;
+	std::cout << *x << ' ' << *y << std::endl;
+	inc(y);
+	std::cout << *x << ' ' << *y << std::endl;
+
+	return 0;
+}