Please Tell me the use of static keyword in the below example & the realtime use of it

I can see two uses of 'static' in that program:

1. The Main() method needs to be static so it can be the program's entry point. If it were an instance method of the EmpTaxDetails class, then you'd need to call that class's constructor first which isn't allowed as the Main method would not then be the entry point i.e. the first method that's called when the program starts.

2. The calcTax method has probably been declared to be static so that you don't have to create a Tax object first in order to call it.

In general, static members are used when they don't apply to a particular instance of their containing class or struct, but to the class or struct as a whole.