What are extension methods
Such a method which can invoke from that class with does not defined in that class.
What is stream reader/writer
Reading/writing information in chunks (step by step)
What is the purpose of ‘using’
It close the corresponding variable at close time automatically and we do not need to close it by ourselves.
If we delete directory with parameter true. what will happen
It will delete directory, even if there are contents in it.
What is reflection
We can examine our assembly (variables, types, values etc) at run time. We can write our object states in files, databases with reflections. It is very useful feature.