当我构建我的 Ulam (Prime) Spiral 时，我不断遇到这个奇怪的问题。我在 SpiralMaker() 中所做的是使用 4 步方法来创建螺旋。只要位置小于数组中的总方格，并且它在第 1 步，那么它应该向右移动 1 步并放置 2。当它到达第 2 步时，它会向上移动 1 并放置 numLocation现在是 3。在第 3 步，它向左移动两次，走 2 步，并将这些位置设置为 4 和 5，依此类推。
但是当我运行它时，我在第 32 行得到以下异常，
线程“主”java.lang.ArrayIndexOutOfBoundsException 中的异常：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;
}
}