I wanted to find a counter example to show that the completeness of the inner product space is necessary in [Riesz representation theorem](https://en.wikipedia.org/wiki/Riesz_representation_theorem). Please give an example of a bounded linear functional $T$ on an incomplete inner product space $X$ which do not have any inner product representation i.e. there does not exist any $z$ in $X$ s.t. $T(x)= \langle ,z\rangle$ for all $x$ in $X$.