Add example of bridge pattern in C++

cpp/patterns/bridge/abstraction.cpp

@@ -0,0 +1,10 @@
+
+#include "abstraction.hpp"
+
+int VerboseCalculator::doMath(const int &a, const int &b) const
+{
+  int result = method->math(a, b);
+  std::cout << "Performing " << method->getName() << " on input: a = " << a
+            << ", b = " << b << std::endl << "Result: " << result << std::endl;
+  return result;
+}