PROGRAM STRUCTURE

This is the program structure,where main section method is essential all other are optional.Where

using directive section includes includes all those namespaces that contains classes required in the application.It tells to the compiler to look for the class in that namespace.

Interface are used when we want to implement the concept of multiple inheritance ina a program.

class are included in class section.And last one is the main section method,Main method is the starting point in a c# program and so is essential part.There can be multiple Main methods in a C# program.

EXECUTING THE PROGRAM: 

             After creating a c program,save it with .cs file extension. Ex: sample.cs

And for compiling it simply type : csc sample.cs