Ex3.4: Static Class Counter

ex3.4/Counter.cc

@@ -0,0 +1,9 @@
+// Counter.cc
+
+#include "Counter.hh"
+
+int Counter::getCounter() {
+	return counter;
+}
+
+int Counter::counter = 0 ;

ex3.4/Counter.hh

@@ -0,0 +1,18 @@
+// Counter.hh
+
+#ifndef COUNTERHH
+#define COUNTERHH
+
+class Counter
+{
+	public:
+		Counter(){ counter++ ; }
+		~Counter(){ counter-- ; }
+
+		static int getCounter();
+
+	
+		static int counter ;
+	
+};
+#endif

ex3.4/main.cpp

@@ -0,0 +1,19 @@
+#include <iostream>
+#include "Counter.hh"
+
+using namespace std;
+
+int main() {
+	Counter a ;
+	Counter b ;
+
+	cout << "there are now "
+		<< Counter::getCounter()
+		<< " Counter objects" << endl;
+
+	if (true) {
+		Counter c;
+		cout << " and now " << Counter::getCounter() ;
+	}
+	cout << " and now " << Counter::getCounter() << endl ;
+}