Question

好的，所以我一直在制作斐波那契系列节目，例如（0 1 1 2 3 5 8 13 21 ..）。我的逻辑很好，但是当我从for（）循环到外面时，存在可变状态问题。如何保持我的＆＃34; firstNumber＆＃34;状态如何？我不知道为什么它打印价值直到19，虽然我给输入值10

public class Fibonacci {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        System.out.println("Enter the number: ");
        int input = scan.nextInt();
        FibonacciFunction(input);

    }
    public static int FibonacciFunction(int x) {
        int firstNumber = 0;
        int i;
        for(i =1; i <= x; i++) {
            int numbers = firstNumber + i;
            System.out.println(numbers);
            firstNumber = i; //Keep this state as it is so that when loop run for the second time "firstNumber" should be 1 not 0 again


        }

        return firstNumber;
    }

}

输出输入数字： 10 1 3 五 7 9 11 13 15 17 19

Answer 1

您的逻辑不正确：您正在将i循环的迭代器值for添加到最后一个数字，但您需要将倒数第二个数字添加到最后一个数字中Fibonacci序列。因此，您的firstNumber变量不应该保持在1或0的“状态”，但随着循环的继续，它应随Fibonacci序列一起增长。

public static int FibonacciFunction(int x) {
    if(x <= 0) return 0;
    int firstNumber = 0, secondNumber = 1;
    for(int i = 0; i < x; i++) {
        int numbers = firstNumber + secondNumber;
        firstNumber = secondNumber;
        secondNumber = numbers;
        System.out.println(numbers);
    }

    return firstNumber;
}

它的打印值直到19，因为函数的参数是您希望打印的Fibonacci值的数量，而不是最大的Fibonacci数。

Answer 2

To solve your error, you are saying that you want firstNumber to not be 0 when it comes out of the for loop. It is impossible for firstNumber to be 0 at the end of the for loop unless the for loop didn't happen. When you say it is coming back 0 that means the forloop is not going, in which case it returns the original value of firstNumber which is 0. This means the value x is incorrect, or the way you read it in is incorrect.

Trying putting in a S.O.P statement after the firstNumber =i; to see what the value actually is:

   public static int FibonacciFunction(int x) {
        int firstNumber = 0;
        int i;
        for(i =1; i <= x; i++) {
            int numbers = firstNumber + i;
            System.out.println(numbers);
            firstNumber = i; 
            System.out.print(" First Number Value: "+ firstNumber);


        }

        return firstNumber;
    }

如何保持我的变量状态？

2 个答案: