Understanding Generics

Understanding Generics:

Generics allow you to delay the specification of the data type of programming elements in a class or a method, until it is actually used in the program. In other words, generics allow you to write a class or method that can work with any data type.

namespace Apps

{

    class UnderstandingGenerics

    {

        static void GenericsTest<T>(T lhs, T rhs)

        {

            Console.WriteLine("{0}, {1}", lhs, rhs);

        }

        static void Main(string[] args)

        {

            int a = 10, b = 2;

            Char c = 'r', d = 's';

            GenericsTest<int>(a, b);

            GenericsTest<char>(c, d);

        }

    }

}

HyperLinks in text file C#

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace HyperLinksFilter
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                StreamReader sfilecontent1 = new StreamReader(@"D:\log");
                StreamWriter dfilecontent2 = new StreamWriter(@"D:\test.txt");
                string line;
                while ((line = sfilecontent1.ReadLine()) != null)
                {
                    //string[] words = line.Split(',');
                    //string k = words[1];
                    //dfilecontent2.Write(k.Trim() + "\r\n");

                    if (line.Contains("http"))
                    {
                        dfilecontent2.Write(line+"\r\n"+"\r\n");
                    }
                }
                sfilecontent1.Close();
                dfilecontent2.Close();
                Console.WriteLine("File created Successfully!");
            }
            catch (Exception ex1)
            {
                Console.WriteLine(ex1.Message);
            }
        }
    }
}

Understanding Static Constructor (C# reference)

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace Apps

{

    class statiConstructor

    {

        private static int a;

        static statiConstructor()

        {

            a = 10;

            Console.WriteLine("Static Constructor with static member value=" + a);

        }

        public static void MethodCall()

        {

            Console.WriteLine("Method Call ");

        }

    }

    class UnderstandingStaticConstructor

    {

        public static void Main()

        {

         // In particular, a static constructor is called once, automatically, when the class is used for the first time.

            statiConstructor k = new statiConstructor();

            statiConstructor.MethodCall();
            statiConstructor.MethodCall();

        }

    }

}

Output:

Static Constructor with static member value = 10
Method Call
Method Call

Understanding Indexer in C#

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace Apps

{

    class IndexerExample

    {

        //private int[] item = new int[11];

        private string[] nameslist = new string[11];

        private int index = 0; 

        public string this[int index]

        {

            get

            {

                return nameslist[index];

            }

            set

            {

                nameslist[index] = value;

            }

        }

        public int this[string indexContent]

        {

            get

            {

                for (int i = 0; i < nameslist.Length; i++)

                {

                    if (indexContent == nameslist[i])

                    {

                        index = i;

                        break;

                    }

                }

                return index;

            }

            set

            {

                for (int i = 0; i < nameslist.Length; i++)

                {

                    if (indexContent == nameslist[i])

                    {

                        nameslist[i] = value.ToString();

                    }

                }

            }

        }

    }

    class UnderstandingIndexer

    {

        public static void Main()

        {

            IndexerExample obj = new IndexerExample();

            obj[4] = "Nagendra";

            // calls the property with return type string

            Console.WriteLine(obj[4]);

            // calls the property with return type int

            Console.WriteLine(obj["Nagendra"]);

        }

    }

}

Indexer an object to be indexed in the same way as an array. Indexer modifier can be private, public, protected or internal. The return type can be any valid C# types.Indexers in C# must have at least one parameter.

Understanding interfaces in C#

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace Apps

{

    // Interface is a collection of abstract members and properties.

    // Unlike the Abstract class the interface cannot contain the non-abstract members.

    interface Iclass1

    {

        // A property in interface can be specified without any body

        int a { set; get; }

        void PrintProperty();

        // Access modifiers for the members of interface defaults to Public

        void Read();

}

    interface Iclass2

    {

        void Write();

}

    class Test9 : Iclass1, Iclass2      // Multiple interfaces

{

       // The class should implement all the methods and properties contained in the interface.(if not gives compile error)

        public int a { set; get; }

        public void Print()

        {

            Console.WriteLine("Non-interface method implemented in class, Value=" + a);

        }

        public void PrintProperty()

        {

            Console.WriteLine(a);

        }

        public void Read()

        {

            Console.WriteLine("Reading example");

        }

        public void Write()

        {

            Console.WriteLine("Writing example");

        }

    }

    class UnderstandingInterfaces

    {

        public static void Main()

        {

            Iclass1 ts = new Test9();

            Iclass2 ts1 = new Test9();

            ts.Read();

            ts1.Write();

            ts.PrintProperty();

            Test9 ts2 = new Test9();

            ts2.Print();

        }

    }

}

Understanding Runtime Polymorphism

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace ConsoleApps

{

    class BaseClass

    {

        public void Normal()

        {

            Console.WriteLine("Base Class print");

        }

        public virtual void RuntimePoly()

        {

            Console.WriteLine("Base Class print");

        }

    }

    class DerivedClass : BaseClass

    {

        public new void Normal()

        {

            Console.WriteLine("Derived Class print");

        }

        public override void RuntimePoly()

        {

            Console.WriteLine("Derived Class print");

        }

    }

class UnderstandingRuntimePolymorphism

{

 public static void Main()

{

           // Here Base class method is called

           BaseClass nm = new DerivedClass();

           nm.Normal();

          // Here Derived class method is called

            // Due to run time decision (late binding or runtime polymorphism)

            // since the methods are overriden with ovveride keyword in derived class

            // and virtual keyword in base class of the methods

           BaseClass poly = new DerivedClass();

           poly.RuntimePoly();

     }

 }

}