A real $r$ is computable,if for any $i\in \mathbb{N}$,the $i$ bits can be outputed by a Turing Machine or an algorithm. So, what is computational complexity or complexity measure of computing the real? Since there is just a Turing Machine or a program without input,what is the computational complexity or complexity measure of computing reals ? Any definition and result? Intuitively, the computational complexity or complexity measure may defined in the term of the size of output, like length of the binary sequence of the outputed real.