C# program to convert Lowercase Characters by Uppercase and Vice-Versa

 using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Collections;

using System.Threading;

using System.IO;

namespace CSharpProgram

{

    class AkbTechie

     {

            static void Main(string[] args)

           {

               string str = "akbtechie";  // original string

               Console.WriteLine("string Lower Case :-" + str);   // string converted to Upper case

               string ConvertedStr = str.ToUpper();

               Console.WriteLine("string Converted Upper Case :-"+ConvertedStr);

               Console.ReadKey(); 

          }

    }

}

output:-

string Lower Case :-akbtechie

string Converted Upper Case :-AKBTECHIE