Show using C++ wrapper API for the "class" example

This almost exactly mirrors the existing C examples, but modify both
examples slightly to make their output show which language is used.

Examples/c/class/Makefile

@@ -5,10 +5,16 @@ CXXSRCS    = example.cxx
 TARGET     = example
 INTERFACE  = example.i
 
-check: build
+check_c: build
 	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' \
 	TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' RUNME_EXT=c c_run
 
+check_cxx: build
+	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' \
+	TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' RUNME_EXT=cxx c_run
+
+check: check_c check_cxx
+
 build:
 	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' CXXSRCS='$(CXXSRCS)' \
 	SWIG_LIB_DIR='$(SWIG_LIB_DIR)' SWIGEXE='$(SWIGEXE)' \

Examples/c/class/runme.c

@@ -3,7 +3,7 @@
 #include "example_wrap.h"
 
 int main(int argc, char **argv) {
-  printf("Creating some objects:\n");
+  printf("Creating some objects from C:\n");
   Circle* c = Circle_new(10);
   printf("    Created circle\n");
   Square* s = Square_new(10);
@@ -37,7 +37,7 @@ int main(int argc, char **argv) {
   Circle_delete(c);
 
   printf("%d shapes remain\n", Shape_nshapes_get());
-  printf("Goodbye\n");
+  printf("Goodbye from C\n");
 
   return 0;
 }

Examples/c/class/runme.cxx

@@ -0,0 +1,41 @@
+#include <iostream>
+
+#include "example_wrap.h"
+
+int main(int argc, char **argv) {
+  { // Block containing the Circle and Square objects.
+  std::cout << "Creating some objects from C++:\n";
+  example::Circle c(10);
+  std::cout << "    Created circle\n";
+  example::Square s(10);
+  std::cout << "    Created square\n";
+
+  std::cout << "\nA total of " << example::Shape::nshapes() << " shapes were created\n";
+
+  c.x(20);
+  c.y(30);
+
+  example::Shape& shape = s;
+  shape.x(-10);
+  shape.y(5);
+
+  std::cout << "\nHere is their current positions:\n";
+  std::cout << "    Circle = (" << c.x() << " " << c.y() << ")\n";
+  std::cout << "    Square = (" << s.x() << " " << s.y() << ")\n";
+
+  std::cout << "\nHere are some properties of the shapes:\n";
+  example::Shape* shapes[] = {&c, &s};
+  for (int i = 0; i < 2; i++) {
+    std::cout << "    " << (i ? "Square" : "Circle") << "\n";
+    std::cout << "    area      = " << shapes[i]->area() << "\n";
+    std::cout << "    perimeter = " << shapes[i]->perimeter() << "\n";
+  }
+
+  std::cout << "\nGuess I'll clean up now\n";
+  }
+
+  std::cout << example::Shape::nshapes() << " shapes remain\n";
+  std::cout << "Goodbye from C++\n";
+
+  return 0;
+}