Definition of open set with examples in real analysis

[MathematicsTuition]

Let S be a subset of R . Then S is said to be a closed set if S' is contained in S ( i.e., S contains all its limit points) so by defintion of closed set, a closed set obviously contains its limit point

[SivaSankar-utbj]

Give the examples for subsets of C are open in C with usual metric