Add in a message that displays when the user selects an index that doesn’t exist in C# console-CodePudding

Hi I'm very new at programming and currently learning C# so please bare with me. I'm currently stuck trying to display an "index does not exist" for the user.Tried different methods but I kept getting errors. I've looked around but could not find something similar to what I'm doing. Here is my current code:

        int[] myNumbers = { 10, 5, 15, 20, 30 };
        Console.WriteLine("User please enter a number from 0 to 4\n");

        int userIndex = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("You chose number: "   myNumbers[userIndex]);

        if (userIndex > 4)
        {
            Console.WriteLine("Index does not exist "   myNumbers[userIndex);
        }
            

        Console.ReadLine();

Thank you.

CodePudding user response：

Try the following which properly asserts out of range.

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] myNumbers = { 10, 5, 15, 20, 30 };
            Console.WriteLine("User please enter a number from 0 to 4\n");

            int userIndex = Convert.ToInt32(Console.ReadLine());

            if (userIndex <= 4)
            {
                Console.WriteLine("Index does not exist "   myNumbers[userIndex]);
            }
            else
            {
                Console.WriteLine($"{userIndex} is out of range ");
            }


            Console.ReadLine();
        }
    }
}

CodePudding user response：

You should change the sequence of the code you have written. Right now, you are attempting to access an array (possibly with an array index that is incorrect).

int[] myNumbers = { 10, 5, 15, 20, 30 };
Console.WriteLine("User please enter a number from 0 to 4\n");

int userIndex = Convert.ToInt32(Console.ReadLine());
if (userIndex > 4)
{
    Console.WriteLine("Index does not exist "   myNumbers[userIndex);
}
else
{
    Console.WriteLine("You chose number: "   myNumbers[userIndex]);
}

Console.ReadLine();