everest% CC cubemain.C cube.C box.C
cubemain.C:
cube.C:
box.C:
everest% 

everest% a.out
Debug: default Box constructor called
Cube debug: l=6.934801 h=1.249837 w=4.158354
number of boxes = 1
Debug: default Box constructor called
Cube debug: l=6.014158 h=1.565003 w=5.977036
number of boxes = 2
Debug: default Box constructor called
c1: I'm a cube. Each side has length=1.000000
c2: I'm a cube. Each side has length=1.200000
b: I am a box with length=4.798199, height=2.557503 and width=8.283001
number of boxes = 3

Compare
Cube c1 fits inside cube c2
Cube c1 fits inside box b

Grow c1
I'm a cube. Each side has length=2.000000
Volume of c1 is now = 8.000000

Shrink c2
I'm a cube. Each side has length=0.600000
Volume of c2 is now = 0.216000
everest%