添加一条消息,当用户选择C#console中不存在的索引时显示该消息

尝试以下正确断言超出范围的方法。

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();
        }
    }
}

你应该改变你写的代码的顺序。现在,您正试图访问一个数组(可能使用了不正确的数组索引)。

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();