Question

I’m basically looking for a way to automate typing stuff like the following:

cout << 'a[' << x << '][' << y << '] =\t' << a[x][y] << endl; 

Something like:

PRINTDBG(a[x][y]); 

Ideally this would also work for

PRINTDBG(func(arg1, arg2)); 

and even

PRINTDBG(if(condition) func(foo);); 

(which would print e.g. ‘if(false) func(5)’).

Nonportable hacks welcome too 🙂

(no, using a debugger isn’t the same, it’s much less flexible and I find it confusing)

Answer 1

This is, in the way you want it, not possible. If you have if(condition) func(foo); given to a macro, it can stringize that stuff, and it will print if(condition) func(foo);, but not with the actual values of the variables substituted. Remember the preprocessor doesn’t know about the structure about that code.

For debugging, i would use some type-safe printf variant like boost.format or some home brew printf with boost.fusion, which make the job of printing stuff like that much more easy:

dprintf('a[%][%] = %', (x, y, a[x][y]));