added drill01-07 for chapter 12

Author: csern

Chapter12/README.md

@@ -0,0 +1,27 @@
+# 12: Class Design
+
+- [Drill](#drill-1)
+- [Review](#review-1)
+- [Terms](terms.txt)
+- [Exercises](#exercise-1)
+
+## [Drill 1](drill/01)
+Define a class `B1` with a virtual function `vf()` and a non-virtual function `f()`. Define both of these functions within class `B1`. Implement each function to output its name (e.g., `B1::vf()`). Make the functions `public`. Make a `B1` object and call each function.
+
+## [Drill 2](drill/02)
+Derive a class `D1` from `B1` and override `vf()`. Make a `D1` object and call `vf()` and `f()` for it.
+
+## [Drill 3](drill/03)
+Define a reference to `B1` (a `B1&`) and initialize that to the `D1` object you just defined. Call `vf()` and `f()` for that reference.
+
+## [Drill 4](drill/04)
+Now define a function called `f()` for `D1` and repeat 1–3. Explain the results.
+
+## [Drill 5](drill/05)
+Add a pure virtual function called `pvf()` to `B1` and try to repeat 1–4. Explain the result.
+
+## [Drill 6](drill/06)
+Define a class `D2` derived from `D1` and override `pvf()` in `D2`. Make an object of class `D2` and invoke `f()`, `vf()`, and `pvf()` for it.
+
+## [Drill 7](drill/07)
+Define a class `B2` with a pure virtual function `pvf()`. Define a class `D21` with a `string` data member and a member function that overrides `pvf()`; `D21::pvf()` should output the value of the `string`. Define a class `D22` that is just like `D21` except that its data member is an `int`. Define a function `f()` that takes a `B2&` argument and calls `pvf()` for its argument. Call `f()` with a `D21` and a `D22`.

Chapter12/drill/01/B1.h

@@ -0,0 +1,15 @@
+#ifndef B1_H
+#define B1_H
+
+#include <iostream>
+
+struct B1 {
+	virtual void vf() const {
+		std::cout << "B1::vf()\n";
+	}
+	void f() const {
+		std::cout << "B1::f()\n";
+	}
+};
+
+#endif

Chapter12/drill/01/main.cpp

@@ -0,0 +1,8 @@
+#include "B1.h"
+
+int main() {
+	B1 b;
+
+	b.vf();
+	b.f();
+}

Chapter12/drill/02/B1.h

@@ -0,0 +1,15 @@
+#ifndef B1_H
+#define B1_H
+
+#include <iostream>
+
+struct B1 {
+	virtual void vf() const {
+		std::cout << "B1::vf()\n";
+	}
+	void f() const {
+		std::cout << "B1::f()\n";
+	}
+};
+
+#endif

Chapter12/drill/02/D1.h

@@ -0,0 +1,12 @@
+#ifndef D1_H
+#define D1_H
+
+#include "B1.h"
+
+struct D1 : public B1 {
+	void vf() const override {
+		std::cout << "D1::vf()\n";
+	}
+};
+
+#endif

Chapter12/drill/02/main.cpp

@@ -0,0 +1,8 @@
+#include "D1.h"
+
+int main() {
+	D1 d;
+
+	d.vf();
+	d.f();
+}

Chapter12/drill/03/B1.h

@@ -0,0 +1,15 @@
+#ifndef B1_H
+#define B1_H
+
+#include <iostream>
+
+struct B1 {
+	virtual void vf() const {
+		std::cout << "B1::vf()\n";
+	}
+	void f() const {
+		std::cout << "B1::f()\n";
+	}
+};
+
+#endif

Chapter12/drill/03/D1.h

@@ -0,0 +1,12 @@
+#ifndef D1_H
+#define D1_H
+
+#include "B1.h"
+
+struct D1 : public B1 {
+	void vf() const override {
+		std::cout << "D1::vf()\n";
+	}
+};
+
+#endif

Chapter12/drill/03/main.cpp

@@ -0,0 +1,12 @@
+#include "D1.h"
+
+int main() {
+	D1 d;
+
+	d.vf();
+	d.f();
+
+	B1& bref = d;
+	bref.vf();
+	bref.f();
+}

Chapter12/drill/04/B1.h

@@ -0,0 +1,15 @@
+#ifndef B1_H
+#define B1_H
+
+#include <iostream>
+
+struct B1 {
+	virtual void vf() const {
+		std::cout << "B1::vf()\n";
+	}
+	void f() const {
+		std::cout << "B1::f()\n";
+	}
+};
+
+#endif