无法将变量添加到我的数组中

时间:2013-05-06 00:49:21

标签: java arrays multidimensional-array indexoutofboundsexception spiral

当我正在构建我的Ulam(Prime)螺旋时,我不断遇到这个奇怪的问题。我在SpiralMaker()中所做的是使用4步法创建螺旋。只要位置小于数组中的总方块,并且它在步骤1,那么它应该向右移动1步并放置2.当它到达步骤2时,它向上移动1并放置numLocation现在是3.在第3步,它向左移动两次,分2步,将这些位置设置为4和5,等等。

但是当我运行它时,我在第32行得到了以下异常,

  

线程“main”中的异常java.lang.ArrayIndexOutOfBoundsException:5

import java.util.Arrays;

public class GridMaker {
    private static int gridRow = 5; // R = length
    private static int gridCol = 5; // C = height
    private static int[][] grid = new int[gridRow][gridCol];
    private static int totalSteps = (gridRow * gridCol); // total blocks on the grid
    private static int numLocation = 1; // location refers to the number in the box, ie. 1, 2, 3, etc.
    private static int rowLength = 1;
    private static int colLength = 1;

    public static void main(String[] args) {
        grid[Calc.findArrayCenter(gridRow)][Calc.findArrayCenter(gridRow)] = 1;
        spiralMaker();

        for (int r = 0; r < gridRow; r++){
            for (int c = 0; c < gridCol; c++){
                System.out.print(grid[r][c] + " ");
            }
            System.out.println("");
        }
    }

    private static void spiralMaker() {
        for (int stepMaker = 0; stepMaker < 4; stepMaker++){//counter for the steps, only needs 1 of these

            if (stepMaker == 1 && numLocation < totalSteps){
                for (int r = 0; r < gridRow; r++){ //starts browsing array for the last number
                    for (int c = 0; c < gridCol; c++){
                        if(grid[r][c] == (numLocation - 0)){ //when it finds the last number
                            for(int i = 0; i < rowLength; i++){
                                grid[r][c + 1] = numLocation + 1; //when 0 no errors, when 1 "java.lang.ArrayIndexOutOfBoundsException"
                            }
                            numLocation++;
                            rowLength++;
                        }
                    }
                }
            }

        }
    }
}

// -----------------------

public class Calc {
    public static int findArrayCenter(int center) {
        int fcenter = 0;
        if (center % 2 != 0)
        fcenter = (int) ((center / 2));
        else
        fcenter = (center / 2);
        return fcenter;
    }

    public static boolean isOdd(int num) {
        boolean result = true;
        if (num % 2 == 0)
        result = false; // false = even, true = odd
        return result;
    }

    public static boolean primeTester(int num) {
        if (num == 1)
        return false;
        if (num % 2 == 0 && num != 2)
        return false;
        for (int primeCheck = 3; primeCheck <= num / 2; primeCheck += 2) {
            if (num % primeCheck == 0 && num != primeCheck)
            return false;
        }
        return true;
    }
}

3 个答案:

答案 0 :(得分:1)

请记住,Java中的数组是零索引的。

更改:

grid[r][c + 1] = numLocation + 1;

grid[r-1][c] = numLocation + 1;

答案 1 :(得分:1)

看起来你正在运行循环太多次迭代。因为数组是[5] [5]并且你使用的是[r] [c + 1],所以你永远不希望c为4。

变化

for(int c = 0; c&lt; gridCol; c ++){

for(int c = 0; c&lt; gridCol-1; c ++){

并查看是否有效

答案 2 :(得分:1)

您正在分配一个二维数组网格[gridRow] [gridCol],它至少是一个5x5数组。在第29行,你从0计数到gridCol(= 4)。在第32行中,您再次递增gridcol(或c)。因此,您正在索引数组的第6个元素,但是,该数组只有5个元素...