Listing 1

class Frog {
public:
	Frog( char *p = "the anonymous frog")
	{
		name = p;
		dist = 0;
		printf( "BEGIN Frog %s\n", name);
	}

	~Frog()    { printf( "END Frog %s\n", name); }

	char *Name()            { return name; }

	virtual void jump(int x) { dist += x; }

	virtual void croak() { printf( "R-R-R-ibit\n"); }

	int distance()          { return dist; }
private:
	char *name;
	int dist;
};

Listing 2

class Newt : public Frog {
public:
	Newt( char *n) : (n) {}

	void jump( int x)
	{
		printf( "I'm a jumping Newt\n" );
		// invoke base class function against
		// this derived class object
		Frog::jump( x);
	}
};

class Salamander : public Frog {
public:
	Salamander( char *n) : (n) {}

	void jump( int x)
	{
		printf( "I'm a jumping Salamander\n" );
		Frog::jump( x);
	}
};

Listing 3

typedef int Truth;
const int dim = 100;

class Stack[T] {        // Stack of T values
public:
	Stack()                 { sp = 0; }

	void push( T x)         { elt[sp++] = x; }

	T pop()                 { return elt[--sp]; }

	Truth isempty()         { return sp <= 0; }

	Truth isfull()          { return sp >= dim; }
private:
	T elt[dim];
	int sp;         // sp is index of next slot available to push
};