n;main(aaa){while(1-printf(&"a%nb"[n],&n));}
Lacking any assignment operators to use for flow control, it seemed a good idea to look for some function which would take an address and write something to it. I found a %n specifier for printf which does this. I think this was the intended general idea. I had to test on ideone because there was some bug in the implementation on my computer where it refuses to write anything after a %n... Something to do with this maybe.