Input Validations in C# at C Sharp for Beginners Course Codeasy.Net

1

Write a program that validates a battleship move. It first reads a letter [A–J] or [a–j] and then an integer [1–10], each from the new line. If the input for the move is valid, program should output “Next move is {letter}{number}.” Otherwise, it should output “Letter should be from A to J. Number from 1 to 10. Try again!” The program should continue to ask for and read values for the battleship move until the user inputs valid values for both of them. Pay attention: it should be case insensitive; ‘A’ and ‘a’ are both allowable. Your program should, however, output letter in the same case as it was entered. For example:

a

Letter should be from A to J. Number from 1 to 10. Try again!

10
a
Letter should be from A to J. Number from 1 to 10. Try again!

10
Letter should be from A to J. Number from 1 to 10. Try again!

c
5
Next move is c5.

using System;

namespace InputValidation
{
    class Battleship
    {
        static void Main(string[] args)
        {
            var letterAsString = Console.ReadLine();
            var numberAsString = Console.ReadLine();

            char letter;
            int number;

            while (!char.TryParse(letterAsString, out letter) || !int.TryParse(numberAsString, out number) || letter < 'a' || letter > 'j' || number < 1 || number > 10)
            {

                Console.WriteLine("Letter should be from A to J. Number from 1 to 10. Try again!");
                letterAsString = Console.ReadLine();
                numberAsString = Console.ReadLine();
            }

            Console.WriteLine($"Next move is {letter}{number}.");
        }
    }
}

Can’t seem to find a way to make it case insensitive. Any help?

2

You are on the right track! I think the condition for while should be a bit more complete: either it is a capital letter or a lower case one.
while (... !( (l >= 'a' && l <= 'j') || (l >='A' && l <= 'J' )) ...)

I think something like this will do. Basically, it checks that the letter is NOT either lowercase or an upper case

Please let me know if it worked!

3 
using System;

namespace InputValidation
{
    class Battleship
    {
        static void Main(string[] args)
        {
            var letterAsString = Console.ReadLine();
            var numberAsString = Console.ReadLine();

            char letter;
            int number;

            while (!char.TryParse(letterAsString, out letter) || !int.TryParse(numberAsString, out number) || !((letter >= 'a' && letter <= 'j') || (letter >= 'A' && letter <= 'J')))
            {

                Console.WriteLine("Letter should be from A to J. Number from 1 to 10. Try again!");
                letterAsString = Console.ReadLine();
                numberAsString = Console.ReadLine();
            }

            Console.WriteLine($"Next move is {letter}{number}.");
        }
    }
}

The program works as intended, I have tried all combinations and didn’t find any errors, but codeasy still doesn’t accept it

4

It seems to me that you are not checking the condition that the number should be from 1 to 10. I entered
> c
> 22

And the output of the program was:

Next move is c22.