Adding delicated constructor example

Author: harris2001

C++11/delicated_constructors.cpp

@@ -0,0 +1,54 @@
+/*
+ * 2. DELIGATED CONSTRUCTORS:
+ *
+ * The following code implements the idea of deligated constructors first introfuced in C++11
+ * This allows an overloaded constructor to avoid code duplication and by deligating some
+ * 	of the work to another constructor of the same class 
+ */
+#include <iostream>
+#include <cassert>
+#include <sstream>
+
+class Foo
+{
+	public:
+	Foo()
+	{
+		a = b = c = 1;
+	}
+	// By extending the default constructor, we delicate part of the work that needs to be done 
+	Foo(int c) : Foo()
+	{
+		this->c = c;
+	}
+
+	private:
+	int a;
+	int b;
+	int c;
+
+	friend std::ostream& operator<<(std::ostream& o, const Foo& f)
+	{
+		o << "(" << f.a << "," << f.b << "," << f.c <<")\n";
+		return o;
+	}
+};
+
+int main()
+{
+	std::cout << "===== Test : Deligated constructor was called =====\n";
+	Foo default_constr;
+	
+	std::ostringstream oss;
+	oss << default_constr;
+	assert(oss.str() == "(1,1,1)\n");
+
+	//Resetting ostring stream
+	oss.str(std::string());
+
+	Foo deligated_constr(3);
+	oss << deligated_constr;
+	assert(oss.str() == "(1,1,3)\n");
+
+	return 0;
+}