| |
Hi,
The answer here depends on your coding style.
If you are using non-derived concrete classes, with simple member data and the
default constructor/destructor, then it costs ~10-20 bytes/class.
If you are using non-derived concrete classes, with member data and non-default
constructor/destructor, then the simplest examples seem to add ~50-200
bytes/class.
If you are using derived concrete classes, with no virtual methods, simple
member data, and the default constructor/destructor, it costs ~50 bytes/class.
If you are using virtual methods, it costs ~200 bytes/class + ~12 bytes/virtual
method.
There is additional overhead for each call to a c++ method, since the class
pointer is an additional argument, or ~4 bytes/call additional overhead. If
you are using inlined functions, this can go away.
The worst case scenario I have seen so far was an implementation of my sensor.H
as an abstract class of sensors, a class for a light sensor, from this abstract
sensor.H. In this case, the pure C code added ~10 bytes, but the c++ code was
~1 KB. The current method takes ~40 bytes. These are very simple classes, so
the overhead is very high!
These numbers a based on gcc-2.95.2 with flags set for optimizing for space.
They also from memory, so take them with a large caveat!
Pat
|
|
Message is in Reply To:
 | | C++ OverHead
|
| Hi all, a simple question ( I hope) I'm running a small GA on my rcx block , and I'm fairly happy qwith my results so far, it evolves well tot he conditions, however I'd like to try something new <g>... I'm going to try to evolve sub-sumptive (...) (24 years ago, 23-Jan-01, to lugnet.robotics.rcx.legos)
|
4 Messages in This Thread:
 
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
