New Core Tutorial

git-svn-id: svn://ultimatepp.org/upp/trunk@10538 f0d560ea-af0d-0410-9eb7-867de7ffcac7

tutorial/CoreTutorial/PolyArray.cpp

@@ -0,0 +1,55 @@
+#include "Tutorial.h"
+
+void PolyArray()
+{
+	/// .Polymorphic `Array`
+
+	/// `Array` can even be used for storing polymorphic elements:
+
+	struct Number {
+		virtual double Get() const = 0;
+		String ToString() const { return AsString(Get()); }
+		virtual ~Number() {}
+	};
+	
+	struct Integer : public Number {
+		int n;
+		virtual double Get() const { return n; }
+	};
+	
+	struct Double : public Number {
+		double n;
+		virtual double Get() const { return n; }
+	};
+	
+	/// To add such derived types to `Array`, you can best use in-place creation with `Create`
+	/// method:
+	
+	Array<Number> num;
+	num.Create<Double>().n = 15.5;
+	num.Create<Integer>().n = 3;
+	
+	DUMP(num);
+	
+	/// Alternatively, you can use `Add(T *)` method and provide a pointer to the newly created
+	/// instance on the heap (`Add` returns a reference to the instance):
+	
+	Double *nd = new Double;
+	nd->n = 1.1;
+	num.Add(nd);
+	
+	DUMP(num);
+	
+	/// Array takes ownership of heap object and deletes it as appropriate. We recommend to use
+	/// this variant only if in-place creation with `Create` is not possible.
+
+	/// It is OK do directly apply U++ algorithms on `Array` (the most stringent requirement of
+	/// any of basic algorithms is that there is `IterSwap` provided for container iterators
+	/// and that is specialized for `Array` iterators):
+	
+	Sort(num, [](const Number& a, const Number& b) { return a.Get() < b.Get(); });
+
+	DUMP(num);
+	
+	///
+}