Introduction: Converting string from lowercase to uppercase without using any inbuilt function, in C#.
Program
  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4. using System.Text;
  5. using System.Threading.Tasks;
  7. namespace LowerTOUpper
  8. {
  9. class LowerTOUpper
  10. {
  11. public static String ConvertToUpperCase(String input)
  12. {
  13. String output = "";
  14. for (int i = 0; i < input.Length; i++)
  15. {
  16. if (input[i] >= 'a' && input[i] <= 'z')
  17. {
  18. output += (char)(input[i] - 'a' + 'A');
  19. }
  20. else
  21. output += input[i];
  22. }
  23. return output;
  24. }
  26. static void Main(string[] args)
  27. {
  28. System.Console.Write("Enter a string: ");
  29. String input = System.Console.ReadLine();
  30. input = ConvertToUpperCase(input);
  31. System.Console.WriteLine("Converted String in Upper Case: " + input);
  32. Console.ReadLine();
  33. }
  34. }
  35. }
Output