如何在c#中的库中使用数组类型来编写斐波那契数列?

I am writing a library featuring several common mathematical methods as a way to hone my skills. I am trying to implement the Fibonacci sequence using arrays. Here is the code in the library:

我正在写一个以几种常用数学方法为特色的图书馆，以此来磨练我的技能。我正在尝试使用数组来实现斐波那契序列。这是图书馆的代码:

     public static int[] Fibonacci(int numElement)
     {
        int n = numElement - 1;
        int[] a = new int[numElement + 1];
        a[0] = 0;
        a[1] = 1;



        for (int i = 2; i <= n; i++)
        {
            a[i] = a[i - 2] + a[i - 1];

        }

      return a;

    }
}

To test it I used a console application in which I referenced my dll:

为了测试它，我使用了一个控制台应用程序，其中我引用了我的dll:

    static void Main(string[] args)
    {
        int[] b = new int[9];
        b = numberTheory.Fibonacci(9);
        foreach (var item in b)
        {
            Console.WriteLine(item);
        }
    }
}

However, this is the output of the above code (9 for input):

然而，这是上述代码的输出(输入的9):

Any other input results in the same output format. How can I fix my code to get the desired output?

任何其他输入结果都是相同的输出格式。如何修改代码以获得所需的输出?

EDIT : it seems that the loop does not iterate irrespective of the position of return statement (or its existence at all).

编辑:似乎循环没有迭代，不管返回语句的位置(或者它的存在)。

3 个解决方案

#1

You are returning prematurely and the wrong type - as pointed by @konked. However the solution provided by him, still has a problem: Fibonacci(9) should be equal to 34 (not 21). So you will need n+1 places in the array.

你过早地返回错误的类型——正如@konked所指出的那样。但是他提供的解决方案仍然有一个问题:Fibonacci(9)应该等于34(不是21)。所以你需要在数组中有n+1个位置。

public int[] Fibonacci(int numElement)
{
     if (numElement < 0)
        throw new ArgumentOutOfRangeException("numElement", numElement, "Fibonnaci number to get must be greater or equal than 0");

        var n = numElement + 1; //you need n+1 positions. The 9th number is in 10th position
        var a = new int[n];
        a[0] = 0;

     if (numElement == 0)
         return a;

    a[1] = 1;

    for (var i = 2; i < n; i++)
        a[i] = a[i - 2] + a[i - 1];

    return a;
}

#2

The generation of the sequence terminates too early. Change it as follows.

序列的生成过早终止。改变它,如下所示。

public static int[] Fibonacci(int numElement)
{
    int n = numElement - 1;
    int[] a = new int[numElement + 1];
    a[0] = 0;
    a[1] = 1;
    for (int i = 2; i <= n; i++)
    {
        a[i] = a[i - 2] + a[i - 1];
    }
    return a;
}

#3

Your return statement is in the wrong place and is returning the wrong type ( element currently in the loop rather than the array ), you're also making some unnecessary variables as well if you change the method to the following it should work

您的返回语句位于错误的位置，并且返回错误的类型(当前在循环中的元素而不是数组)，您也在做一些不必要的变量，如果您将方法更改为下面的方法，那么它应该可以工作。

public static int[] Fibonacci(int numElement)
{
    int[] a = new int[numElement];
    a[0] = 0;
    a[1] = 1;


    for (int i = 2; i < numElement; i++)
    {
        a[i] = a[i - 2] + a[i - 1];
    }

    return a;
}

You can also check out a working fiddle here : https://dotnetfiddle.net/dWZck8

您还可以在这里查看一个工作的小提琴:https://dotnetfiddle.net/dWZck8。

#1

public int[] Fibonacci(int numElement)
{
     if (numElement < 0)
        throw new ArgumentOutOfRangeException("numElement", numElement, "Fibonnaci number to get must be greater or equal than 0");

        var n = numElement + 1; //you need n+1 positions. The 9th number is in 10th position
        var a = new int[n];
        a[0] = 0;

     if (numElement == 0)
         return a;

    a[1] = 1;

    for (var i = 2; i < n; i++)
        a[i] = a[i - 2] + a[i - 1];

    return a;
}

#2