polymorphism

Instructions for the "polymorphism" exercise

Step 1

• look at the code
• open trypoly.cpp
• create a Pentagon, call its perimeter method
• Compile via make, execute via ./trypoly
  • you may have to add current directory to your LD_LIBRARY_PATH :

  export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:.

• create an Hexagon, call its perimeter method
• recompile and check what happens

Step 2

• create an Hexagon, call its parent’s perimeter method
• recompile and check again
• retry with virtual methods

Instructions for the "compiler chain" exercise

• preprocess Polygons.cpp (g++ -E -o output)
• compile Polygons.o and trypoly.o (g++ -c -o output)
• use nm to check symbols in .o files
• look at the Makefile
• try make clean; make
• see linking stage using g++ -v
  • just add a -v in the Makefile command for trypoly
  • run make clean; make
  • look at the collect 2 line, from the end up to -o trypoly
• see library dependencies of trypoly and Polygons.so with ldd
  • On OS X, use otool -L for a similar effect