the thing is that if i use the old project for coding...i will not use all of feature of software....
for example: i can not debug
code::block told me that you just can debug when you have a active project it means that i have to creat a new project anytimes i am coding.
I'm not sure if you are trolling or not, but here's the real answer you need to hear:
Creating a new project is a trivial and necessary operation which takes only a few seconds at most to complete. There is absolutely no justification for trying to take a shortcut here.
The IDE, like any tool, must be learned to be useful. There is no shortcut to learning to use it properly. Code::Blocks is a particularly friendly IDE so again, there is no justification for trying to avoid clicking Project→New.
In terms of what is a "waste of time" you have already spent more time on trying to take a misguided shortcut than it is worth. Learn how to prioritize what is actually a waste of time, then work on that.