有没有办法声明一个具有固定 int 大小的浮点数组？ [复制]

Question

有没有办法声明一个包含浮点变量并且具有固定大小的 int 的数组？

int balls = 5;
float array posX[balls];
private float posY[] = 0;

基本上，我想创建一个数组，以便每个球都可以拥有自己的 XY 坐标，而无需创建少量新变量。我收到错误消息说我有错误的数组声明（第 3 行）并且 posX 和 Balls 在当前上下文中不存在（第 2 行）。上面的代码是我的一些尝试和错误。我正在制作一个 xamarin 表单应用程序，所以也许这与它有关？我的完整代码是这样的：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using SkiaSharp;
using SkiaSharp.Views.Forms;
using System.Runtime.InteropServices.ComTypes;
using System.Runtime.CompilerServices;
using System.Linq.Expressions;
using Xamarin.Forms.Internals;

namespace Ball_Bounce
{
    public partial class MainPage : ContentPage
    {
        int balls = 5;
        float array posX[balls];
        private float posY[] = 0;
        float dx = 5;
        float dy = 5;
        int ballD = 100;
        bool gravity = false;
        float time = 1f / 60;
        float mass = 10;
        float g = -9.8f;
        float forceOnWalls = 0;
        int bounces = 0;
      

                        

        SKPaint blackFillPaint = new SKPaint
        {
            Style = SKPaintStyle.Fill,
            Color = SKColors.Black
        };

        SKPaint Ball = new SKPaint
        {
            Color = SKColors.Black,

        };
        public MainPage()
        {
            InitializeComponent();

            Device.StartTimer(TimeSpan.FromSeconds(1f / 60), () =>
               {
                   CanvasView.InvalidateSurface();
                   return true;
               });
            
        }

        private void CanvasView_PaintSurface(object sender, SKPaintSurfaceEventArgs e)
        {
            SKSurface surface = e.Surface;
            SKCanvas canvas = surface.Canvas;
            canvas.Clear(SKColors.SteelBlue);
            float width = e.Info.Width;
            float height = e.Info.Height;
            canvas.Translate(width / 2, height / 2);


            posX += dx;
            posY += dy;
            if (gravity == false)
            {
                bounces = 0;
                if (posX >= width / 2 - ballD|| posX <= -width / 2 + ballD)
                {
                    dx = -dx;
                }
                else if (posY >= height / 2 - ballD|| posY <= -height / 2 + ballD)
                {
                    dy = -dy;
                }
            }
            else if (gravity == true)
            {

                if (bounces >= 8)
                {
                    dy = 0;
                    posY = height / 2 - ballD;
                }
                dy = Gravity(dy, time);
                if (posX >= width / 2 - ballD || posX <= -width / 2 + ballD)
                {
                    dx = -dx;
                }
                else if (posY >= height / 2 - ballD || posY <= -height / 2 + ballD)
                {
                    dy = -dy+dy/5;
                    bounces += 1;
                }
                

                //forceOnWalls = mass * Math.Abs(dy);
                //if (posY < height / 2 + 11*ballD/10)
                //{


                //    dy = Gravity(dy, time);

                //    if (posX >= width / 2 - ballD || posX <= -width / 2 + ballD)
                //    {
                //        dx = -dx;
                //    }
                //    else if (posY > (height / 2) - (ballD + 10))
                //    {
                //        dy = -dy + 2f; //slows bouncing
                //    }
            }



                //else if (posY >= height / 2 - 9 * ballD / 10 && posY <= height / 2 - 2 * ballD && (forceOnWalls < 1 && forceOnWalls > 0))
                //{
                //    if (posX >= width / 2 - ballD || posX <= -width / 2 + ballD)
                //    {
                //        dx = -dx;
                //    }
                    
                //    posY = height / 2 - ballD;
                //    dy = 0;


                

            

            
            canvas.DrawCircle(posX, posY, ballD, blackFillPaint);



        }
        void OnToggled(object sender, ToggledEventArgs e)
        {
            if (gravity == true)
            {
                dy = -5;
                gravity = false;
                
            }
            else
            {
                gravity = true;
            }
        }
        void OnSpeedValueChanged(object sender, ValueChangedEventArgs args)
        {
            double value = args.NewValue;
            float valueF = Convert.ToSingle(value);
            float signX = Math.Sign(dx);
            float signY = Math.Sign(dy);
            dx = valueF * signX;
            dy = valueF * signY;            
        }
        void OnGravityValueChanged(object sender, ValueChangedEventArgs args) //slider that controls 
        {
            double value = args.NewValue;
            float valueF = Convert.ToSingle(value);
            g = valueF;
        }
        public static float Gravity(float vOld, float time) //calculates the dy changes 
        {
            float g = 15f;
            float vNew = vOld + g * time;
            return vNew;
            
        }
    }
}

Answer 1

这是一个固定大小 (10) 的浮点数组

float[] array = new float[10];

为了防止你的错误，在构造函数中做你的赋值

namespace Ball_Bounce
{
    public partial class MainPage : ContentPage
    {
        int balls;
        float[] array;
        private float posY;
    ....
  
    public MainPage() 
    {
       balls = 5;
       array = new float[balls];
       posY = 0;
    }