Compiling Code

C++ uses separate compilation and linking
Compile code to object files
Link object files to produce executable
g++  -c  file1.cc
compiles file1.cc to give  file1.o
g++  -c  file2.cc
compiles file2.cc to give  file2.o
g++  -o  prog  file1.o  file2.o
links objects files to produce  prog