Java-螺旋方陣

用Java實現螺旋方陣
螺旋方陣：是指呈螺旋狀的矩陣。

具體實現如下：

public void screwMatrix() {
        System.out.print("請輸入數字：");
        Scanner input = new Scanner(System.in);
        int number = input.nextInt();

        int[][] matrix = new int[number][number];
        int max = number * number;
        int row = 0, col = 0;
        int direction = 0;
        for (int j = 1; j <= max; j++) {
            matrix[row][col] = j;
            switch (direction) {
                case 0 :
                    if (col + 1 >= number || matrix[row][col + 1] > 0) {
                        direction += 1;
                        direction %= 4;
                        row += 1;
                    } else {
                        col = col + 1;
                    }
                    break;
                case 1 :
                    if (row + 1 >= number || matrix[row + 1][col] > 0) {
                        direction += 1;
                        direction %= 4;
                        col -= 1;
                    } else {
                        row = row + 1;
                    }
                    break;
                case 2 :
                    if (col - 1 < 0 || matrix[row][col - 1] > 0) {
                        direction += 1;
                        direction %= 4;
                        row = row - 1;
                    } else {
                        col = col - 1;
                    }
                    break;
                case 3 :
                    if (row - 1 < 0 || matrix[row - 1][col] > 0) {
                        direction += 1;
                        direction %= 4;
                        col += 1;
                    } else {
                        row = row - 1;
                    }
                    break;
                default :
                    System.out.println("ERROR");
                    System.exit(0);
            }
        }
        for (int j = 0; j < number; j++) {
            for (int k = 0; k < number; k++) {
                // 判斷輸出最大數的長度
                int size = ((number * number) + "").length();

                for (int i = 0; i <= (size - (matrix[j][k] + "").length() + 1); i++) {
                    System.out.print(" ");
                }
                System.out.print(matrix[j][k]);
            }
            System.out.println("");
        }
    }