java - 数组容器不足以容纳所有需要的值

Question

该程序找到从 1 开始的斐波那契数列，然后将 2 位数字分开，使其不会太大，然后对数字进行阶乘并相加。
我的问题是它缺少序列中的最终值，因为数组不够大，但是如果我更改它，它会给我 java.lang.ArrayIndexOutOfBoundsException 错误(异常)

 int sum = 1;
    int input;

    System.out.print("Enter a number: ");
    input = console.nextInt();

    int[] fib = new int[input];
    int[] out = new int[input];
    int[] fib2 = new int[input];

    fib[0] = 0;
    fib[1] = 1;

    fib2[0] = 0;
    fib2[1] = 1;
    if (input > 0) {

        if (input <= 7) { // for numbers 1,1,2,3,5,8 
            for (int i = 2; i < input; i++) {
                fib[i] = fib[i - 1] + fib[i - 2];
                out[i] = factorial(fib[i]);

            }
        } else { // this is for the 2 digit numbers 13,21,34,55,89
            for (int i = 2; i < input; i++) {
                fib[i] = fib[i - 1] + fib[i - 2];
                fib2[i] = fib2[i - 1] + fib2[i - 2];
            }
            for (int i = 2; i < input; i++) {
                fib[i] = separate(fib[i]);
                fib2[i] = separate2(fib2[i]);
                out[i] = factorial(fib[i]) + factorial(fib2[i]);
            }

        }

        for (int i : out) {
            sum = sum + i;
        }
        System.out.println(sum);
}

输出是 40,490 但应该是 40,730一切正常，除了如果我输入 10，它会缺少最终值 55。计算是这样的 1!+1!+2!+3!+5!+8!+1!+3!+2!+1!+3!+4!+5!+5! = 40,730

Answer 1

当您不知道 array 将存储多少数据时，您应该使用 ArrayList 而不是 Array。

ArrayList 与 Array

略有不同

您可以了解有关ArrayList的更多信息here .

用我的代码替换您给定的代码:-

int sum = 1;
int input;

System.out.print("Enter a number: ");
input = console.nextInt();

ArrayList<Integer> fib = new ArrayList<Integer>();
ArrayList<Integer> out = new ArrayList<Integer>();
ArrayList<Integer> fib2 = new ArrayList<Integer>();

fib.add(0);
fib.add(1);

fib2.add(0);
fib2.add(1);
if (input > 0) {

    if (input <= 7) { // for numbers 1,1,2,3,5,8 
        for (int i = 2; i < input; i++) {
            fib.add(i, fib.get(i - 1) + fib.get(i - 2));
            out.add(i, factorial(fib.get(i)));

        }
    } else { // this is for the 2 digit numbers 13,21,34,55,89
        for (int i = 2; i < input; i++) {
            fib.add(i, fib.get(i - 1) + fib.get(i - 2));
            fib2.add(i, fib2.get(i - 1) + fib2.get(i - 2));
        }
        for (int i = 2; i < input; i++) {
            fib.add(i, separate(fib.get(i)));
            fib2.add(i, separate2(fib2.get(i)));
            out.add(i, factorial(fib.get(i)) + factorial(fib2.get(i)));
        }

    }

    for (int i : out) {
        sum = sum + i;
    }
    System.out.println(sum);
}