C#从主类调用一个带参数的方法

Question

So I have this program where basically what I'm trying to do is to generate a random array of 20 elements and then shift the values in it a number of places according to a value inputted by the user. So if the user inputs 5, the array will shift 5 places and the outputted array will have at its first index [0] the value of the index [6] (since index starts from 0 -> 5+1) and at index [1] the value of the original index [7] and so on.

The problem I'm facing lies with the input parameters. I'm trying to give in the value given by the user, so if the user inputs 5 then I give the "shiftValueX" to the method as "_shiftValueX" to work with it.

Yet below at the "ToString" method where I'm printing out the "shiftPos()" method I'm getting this error, "There is no argument given that corresponds to the required formal parameter". What should I do? I tried putting parameters to the method calling at the ToString section but nothing works. Am I calling the method in a wrong way? How can I fix it? Thank you so much.

This is the Class "Arrays"

class Arrays
{
    //constants
    public const int AMOUNT_OF_VALUES = 20;
    public const int MAX_RND_VALUES = 100;

    private int[] array = new int[AMOUNT_OF_VALUES];


    //Random Generator
    private static Random rnd = new Random();

    //Class Constructors
    public Arrays(int[] num)
    {
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = num[i];
        }
    }

    public Arrays()
    {
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = rnd.Next(MAX_RND_VALUES);
        }
    }

    //Methods
    public int[] shiftPos(int _shiftValueX)
    {
        int y = 0;
        int[] array2 = new int[AMOUNT_OF_VALUES];

        for (int i = _shiftValueX; i <= (array.Length - 1); i++)
        {
            array2[y] = array[i];
            y++;
        }

        for (int i = 0; i < (array.Length - (_shiftValueX)); i++)
        {
            array2[y] = array[i];
            y++;
        }

        return array2;
    }

    //Override ToString Method
    public override string ToString()
    {
        return "The original array was: " + string.Join(", ", array.Select(v => v.ToString())) + "\n" +
               "The rotated array is: " + string.Join(", ", shiftPos().Select(v => v.ToString()));
                              //This is where I'm getting the error ^

    }
}

This is the "Main Program"

class Program
{
    //constants
    public const int AMOUNT_OF_VALUES = 20;

    static void Main(string[] args)
    {

        Console.WriteLine("How many places will the values be shifted: ");
        int shiftValueX = int.Parse(Console.ReadLine());

        Arrays myArray = new Arrays();

        myArray.shiftPos(shiftValueX);
        Console.WriteLine(myArray);
    }
}

Answer 1

Right, fact is you're logic is a little off. As MarcoLaser stated before as well when you call your myArray.shiftPos(shiftValueX); in your main you use a separate array which you then return. This means your array inside of your Arrays class remains unchanged.

What you should most likely do is change the array inside of your Arrays instance in the shiftPos method. You can still return your second array but you should also set the array

    this.array = array2;
    return array2;

This way you can use the private array stored in your instance inside the toString() override instead of calling the shiftPos in the toString.

You also stated you need the original array as well so just store the array2 in a different private variable.

A different way of approaching this, though a bit weird, is too have shiftPos not actually execute the logic but make it store the user value in the class instance so you can use the user parameter in the toString method. Though this is kind of a strange way of approaching it and I suggest you do the first method.