faves.cpp

#include <tuple>
#include <utility>

// Smart pointers

	struct SampleStruct
	{
		int x = 0;
		
		SampleStruct(int a, int b, int c)
			: x(a*b+c)
		{}
	};
	
	void sample_smart_ptr()
	{
		auto ptr = std::make_unique<SampleStruct>(7, 42, 69);
		ptr->x = 13;
	}
	// ptr automatically deleted.

// Factory (CRTP)

	class Base
	{
		public:
		virtual ~Base() = 0;
		virtual std::unique_ptr<Base> clone() const = 0;
	};
	
	inline Base::~Base()
	{}
	
	template <typename Child>
	class Factory
		: public Base
	{
		virtual std::unique_ptr<Base> clone() const override
		{
			auto const& self = static_cast<Child const&>(*this);
			return std::make_unique<Child>(self);
		}
	};
	
	class SampleChild
		: public Factory<SampleChild>
	{};
	
	//
	
	void sample_factory()
	{
		std::unique_ptr<Base> ptr1 = std::make_unique<SampleChild>();
		std::unique_ptr<Base> ptr2 = ptr1->clone();
	}

// Static type ID

	int make_id()
	{
		static int id = 0;
		return ++id;
	}
	
	template <typename T>
	int getID()
	{
		static int id = make_id();
		return id;
	}
	
	//
	
	void sample_static_id()
	{
		int id_int    = getID<int>();    // == 1
		int id_double = getID<double>(); // == 2
		int id_bool   = getID<bool>();   // == 3
	}

// Range-based for loops

	// C++03
	int sample_ranged_03(vector<int> const& nums)
	{
		int sum = 0;
		{
			vector<int>::const_iterator _iter = nums.begin();
			vector<int>::const_iterator _end  = nums.end();
			for (; _iter != _end; ++_iter)
			{
				int const& i = *_iter;
				sum += i;
			}
		}
		return sum;
	}
	
	// C++11
	int sample_ranged_11(vector<int> const& nums)
	{
		int sum = 0;
		for (auto&& i : nums)
			sum += i;
		return sum;
	}

// Stopwatch

	struct Stopwatch
	{
		using Clock = std::chrono::high_precision_clock;
		using Unit = std::chrono::nanosecond;
		
		Clock::time_point st;
		
		void start()
		{
			st = Clock::now();
		}
		
		Unit stop() const
		{
			auto stp = Clock::now();
			return std::chrono::duration_cast<Unit>(stp-st);
		}
	};
	
	//
	
	void sample_stopwatch()
	{
		Stopwatch sw;
		Stopwatch::Unit dur;
		
		sw.start();
		expensive_operation();
		dur = sw.stop();
		
		std::cout << "Benchmark: " << dur << "ns" << std::endl;
	}