Question

我正在尝试使用C＃准备Turtle图形解决方案。一切工作正常，但由于StackOverflowException而终止于进程终止。我检查了this 和 this 问题是吸气塞特或无限循环。但是我的代码中没有任何这种情况。我是C＃的新手。下面是我的代码。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TurtleGraphics
{
    class Program
    {/**
     * Directions: 0 right, 1 down, 2 left, 3 up
     */
        private static short direction = 0;
        private static bool penDown;
        private static int turtleX = 0, turtleY = 0;
        private static int[,] floor = new int[20, 20];


        public static void Main(String[] args)
        {
            initFloor(floor);
            //Scanner in = new Scanner(System.in);
            printMenu();
            int nextCommand = int.Parse(Console.ReadLine());
            while (nextCommand != 9)
            {
                switch (nextCommand)
                {
                    case 1:
                        penDown = false;
                        break;
                    case 2:
                        penDown = true;
                        break;
                    case 3:
                        direction++;
                        break;
                    case 4:
                        direction--;
                        break;
                    case 5:
                        Console.WriteLine("How many steps do you want to move?");
                        int move = int.Parse(Console.ReadLine());
                        if (move <= 10)
                            while (--move != 0)
                             Moves();
                        break;
                    case 6:
                        printArray();
                        break;
                    default:
                        Console.WriteLine("Unknow command, please try again:\n");
                        break;
                }
                Moves();
                Console.WriteLine("What's next?");
                nextCommand = int.Parse(Console.ReadLine());
            }
        }

        private static void initFloor(int[,] floor)
        {
            for (int i = 0; i < floor.GetLength(0); i++)
            {
                for (int j = 0; j < floor.GetLength(1); j++)
                {
                    floor[i,j] = 0;
                }
            }
        }

        private static void printMenu()
        {
            Console.WriteLine("Commands List:\n\n\t1 Pen up\n"
                        + "\t2 Pen down\n"
                        + "\t3 Turn right\n"
                        + "\t4 Turn left\n"
                        + "\t5 to 10 Move forward 10 spaces (replace 10 for a different number of spaces)\n"
                        + "\t6 Display the 20-by-20 array\n"
                        + "\t9 End of data (sentinel)Please enter a command number:\n");
        }

        private static void printArray()
        {
            for (int i = 0; i < floor.GetLength(0); i++)
            {
                for (int j = 0; j < floor.GetLength(1); j++)
                {
                    // Console.WriteLine(floor[i, j]);
                    // Console.WriteLine("  ");
                    if (floor[i, j] == 0)
                        Console.Write(".");
                    else if (floor[i, j] == 1)
                        Console.Write("*");
                    else if (floor[i, j] == 2)
                        Console.Write("T");

            }
                Console.WriteLine();
            }
        }

        private static void Moves()
        {
            switch (direction)
            {
                case 0:
                    turtleX++;
                    break;
                case 1:
                    turtleY++;
                    break;
                case 2:
                    turtleX--;
                    break;
                case 3:
                    turtleY--;
                    break;
                default:
                    if (direction < 0)
                        direction = 3;
                    else
                        direction = 4;
                    Moves();
                    break;
            }
            if (penDown)
            {
                if (turtleX < 20 && turtleY < 20)
                    floor[turtleX, turtleY] = 1;
                else
                {
                    direction -= 2;
                    Moves();
                }
            }

        }
    }
}

感谢您提供任何快速帮助。谢谢

Answer 1

在一种明显的情况下，您最终会无休止地循环。假设您正在输入Moves方法，而direction是4：

    private static void Moves()
    {
        switch (direction)
        {
            case 0:
                //Nope
            case 1:
                //Nope
            case 2:
                //Nope
            case 3:
                //Nope
            default:
                if (direction < 0)
                    //Nope
                else
                    direction = 4; //Okay, but it already was
                Moves(); //And call myself again

代码无法取得进一步的进展，并且调用堆栈中充满了对Moves()的调用，这些调用永远都不会结束。

我无法提供更正，因为我不了解您的代码打算做什么。使用更清晰的方法名称和描述做什么的XML文档注释将其分解为更小的方法。然后确保代码和注释一致。

我不知道名为Moves的方法的正确操作是什么。

Answer 2

Moves中switch语句的默认部分应为：

        default:
            if (direction < 0)
                direction += 4;
            else
                direction -= 4;
            Moves();
            break;

因为它的目的是包装方向值，使其始终保持在0-3范围内。

Turtle Graphics-进程由于StackOverflowException而终止

2 个答案: