递归斐波那契，打印出第一个斐波那契元素 [英] recursive fibonacci that prints n first fibonacci element

问题描述

嗨朋友们。



我想写一个递归函数将N个第一个元素打印到递归函数中。

但我不知道怎么做？

例如召回Fib（8），然后它应该打印0 1 1 2 3 5 8 13



谢谢。

Hi friends.

I want to write a recursive function to print N first element into the recursive function.
But i dont know how do it?
for example recalling Fib(8), then it should print 0 1 1 2 3 5 8 13

thanks.

推荐答案

如果你尝试用递归的方法解决

这样的功能：

If you try to solve with recursive approch
with a fucnction like this :

int F(int n)
{
   if(n==0 || n==1){
         cout<<1<<" ";
   return 1;
   }
   int RET=F(n-2)+F(n-1);
   cout<<RET<<" ";
}

这个函数是O（2 ^ N）



i建议你Dyanmic approch

首先尝试填写表格F []

this Function would be O(2^N)

i suggest you Dyanmic approch
First try to fill a Table of F[]

int F[maxn];
F[0]=F[1]=1;

for(int i=2;i<maxn;i++)>
   F[i]=F[i-1]+F[i-2];

现在你已经在时间顺序为O（N）的数组中保存Fibonacci序列

now you have Fibonacci Sequenced Saved in An Array with The Time Order O(N)

如何定义递归函数在C / C ++中：

How to define a recursive function in C/C++:

int foo(int n) {
   int result = 0;
   // step 0: pin down the result value(s) for starting the recursion
   const int first_value = 1; 
   // step 1: test if you're at the root of the recursion
   if (0 == n)
      result = first_value;
   else {
      // step 2: determine previous result through recursion
      int previous_result = foo(n-1);
      // step 3: determine result from previous result
      result = n*previous_result;
   }
   return result;
}

注意：

- 如果递归需要多于1个值来计算，则步骤0可能需要多个值下一个。

- 如果您有多个起始值，第1步可能需要多次检查

- 奖励提示：您应该添加额外的支票（例如 if（n< 0））以确保你有一个有效的参数，并且不会意外地遇到无限循环。



阅读并理解注释以使此示例代码适应斐波那契序列。我不会那样做，因为它闻起来有作业，如果我为你做的话，我无法帮你学习。

Notes:
- step 0 may require more than one value if your recursion requires more than 1 value to calculate the next one.
- step 1 may require multiple checks if you have multiple starting values
- bonus hint: you should add an additional check ( e. g. if (n < 0) ) to make sure you have a valid argument and won't accidentally run into an endless loop.

Read and understand the notes to adapt this example code for the fibonacci sequence. I won't do that for you since it smells of homework, and I can't help you learn if I do it for you.

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