Question

java,以下这段程序报错，请高手指点。

public class FeiBoNa {
public static void main(String[] args) {
int[] number = null;
number[0] = 0;
number[1] = 1;
number[2] = 1;
int m;
for(m=3;m<30001;m++){
number[m] = number[m-1]+number[m-2];
}
System.out.print(number[m]);
}
}

错误：Exception in thread "main" java.lang.NullPointerException
at FeiBoNa.main(FeiBoNa.java:6)
两个空格没有粘贴，就以上代码而言，错误为：at FeiBoNa.main(FeiBoNa.java:4)。number[0] = 0 当中，"number"带有黄色下划线警告，警告内容为：Null pointer access: The variable number can only be null at this location。

Answer 1

package com.baidu;

public class FeiBoNa {
public static void main(String[] args) {
int[] number = new int[30002]; //你给的是null肯定会报空指针
number[0] = 0;
number[1] = 1;
number[2] = 1;
int m;
for (m = 3; m < 30001; m++) {
number[m] = number[m - 1] + number[m - 2]; //这个地方,你把num数组的下标取到30000去了,所以他的长度必须得是30001
}
System.out.print(number[m]);//这个地方你打印的是number[30001]所以长度必须是30002
}
}

Answer 2

int[] number = null;
这句不对，数组必须初始化才行，比如 int[] number = new int[3];

Answer 3

数组的声明有问题
int[] number = new int[30002];