csharp lesson-4

                                                                           Muthu karthikeyan,Madurai

Basic structure of c sharp program.

using System;

    class Welcome

    {

        static void Main(string[] args)

        {

            Console.WriteLine("hai suresh");          

        }

    }

First line System is a namespace. it contains library class which contain codings to be executed . here understand that namespace is collection of classes..

Next we declared the class named welciome.in c# every thing must be(method,interfacr,properties etc) inside the class like java.

Next we have Main() method . it is a method which be first executed  on starting of the program. Note one thing unlike c,c++,java which have small m in main here we have capital M Main.

Console is a library class which contains methods to get input and write output. Here we used WriteLine method to print output.

if we removed the firstline

using System;

then the coding to print the output will be

     System.Console.WriteLine("hai suresh");          

it will be good until you used only one use of Console class. But if you have multiple lines of code using Console class Then using System declaration will be good.

Next one interactive program.

using System;

namespace ConsoleApplication2

{

    class Program

    {

        static void Main(string[] args)

        {

            Console.WriteLine("enter your tamil mark");

            String mark = Console.ReadLine();

            int Tmark = Int32.Parse(mark);

            Console.WriteLine("Tamil mark=" +Tmark);

        }

    }

}

mark is the variable which will be of string typewe have to convert it into int by using

Int32.Parse.

printing output by WriteLine may also be done by using place holders.

for example

Console.WriteLine("tamil mark={0}",Tmark);

if you have 2 outputs then

Console.WriteLine("tamil mark={0}, English mark={1}”,Tmark,Emark);

The place holders like {0},{1} will be replaced by the data contained by the variables in Tmark, Emrk etc

                                                                    to be continued