Question

Write an application named EnterUppercaseLetters that asks the user to type an uppercase letter from the keyboard. If the character entered is an uppercase letter, display OK; if it is not an uppercase letter, display an error message. The program continues until the user types an exclamation point. C# C# C#

Answer 1

Answer:

The solution code is given below

1. using System;
2. using System.Linq;
3.      
4. public class Program
5. {
6. public static void Main()
7. {
8.  string[] letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T","U", "V", "W", "X", "Y", "Z"};
9.  
10.  Console.WriteLine("Please input a letter: ");
11.  string input_letter = Console.ReadLine();
12.  
13.  if(letters.Contains(input_letter)){
14.   Console.WriteLine("OK");
15.  }else{
16.   Console.WriteLine("Error. Not uppercase letter.");
17.  }  
18. }
19. }

Explanation:

Firstly we import the necessary libraries, System and Linq (Line 1-2).

Next we create a string array to hold all uppercase letters (Line 8).

Next, we prompt user to input a letter using the ReadLine() method (Line 10 - 11)

At last, we define if and else conditions to check if the letters contains the input letter. If so, print ok else print an error message. (Line 13-17)