using System;

​

​

public class classA

{

    public int var;

public classA()  //constructor

{

Console.WriteLine("inside constructror of parent");

    var=34;

}

public void display()

{

    Console.WriteLine("value of a ={0}", var);

}   

​

}

public class child : classA

{

    public child()

    {  

        Console.WriteLine("inside constructror of child");

    }

​

​

}

​

public class Program

    {

    public void func(classA obj)

    {

        Console.WriteLine(obj.var);

    }

    public static void Main()

    {

        /*

        int a=77;

        int b=9;

        Console.WriteLine(a + b +"hello");

        Console.WriteLine("a says i have {0} tomatoes and its {1} hours {2} minutes", 3,4,30);

        classA obj= new child();  //polymorphism

        //obj.display();

        string s="75";

        s= a.ToString();

                Console.WriteLine(s);

        int d=Convert.ToInt32(s);

                        Console.WriteLine(d);

        if(obj is classA && obj is child)

        {

            Console.WriteLine("it is");

        }

        Program pr= new Program();

        pr.func(obj);

        int[] arr=new int[3];

        arr[0]=34; arr[1]=45; arr[2]=56;

        int i;

        for (i=0;i<3;i++)

        {

            Console.WriteLine("at position {0} in array is {1}",i,arr[i]);

        }

        */

        string str1="naveen";

        string str2="verma";

        char[] str1tochar=str1.ToCharArray();

        str2.CopyTo(0,str1tochar,1,3);

        String arrtostr=String.Join("",str1tochar);

        Console.WriteLine(arrtostr);

        string str3=str1.Substring(2);

        Console.WriteLine(str3);

        string[] stArray= {"hello", "my", "name","is","naveen"};

        string str4=String.Join(" ",stArray);

        Console.WriteLine(str4);

        string str5=str1;

        Console.WriteLine(str1.Equals(str5));

        Console.WriteLine(str2.IndexOf("er"));

        string str6=str1.Insert(1,"fr");

        Console.WriteLine(str6);

        string str7=String.Join(" ",stArray,0,2);

        Console.WriteLine(str7);

​

    }

}