如何在不使用递归的情况下使用int返回类型方法返回FIbonacci序列？

Question

我试图在Java中创建一个方法，它打印fib序列，直到传递给该方法的数字。我的问题是，我需要使用int返回类型来返回序列，而我不能使用递归。

public void fibonacci(int num) {
    int a = 0;
    int b = 0;
    int c = 1;
      

    for (int i = 0; i < num; i++) {
        a = b;
        b = c;
        c = a + b;
        System.out.print(c + ", ");
    }
}

public int fibonacci(int num) {
   
    //some code...

    return x; //This is what confuses me. I know this isn't right.
}

//Method call in driver class.
fibonacci(5);

//This would print to console.
1, 1, 2, 3, 5

Answer 1

您可以使用等式[(h)^a-(j)^a]*[1/SQRT(5)]。

• 'a'是所需的斐波那契数
• 'h'是[1+sqrt(5)]/2
• 'j'是[1-sqrt(5)]/2

public static int returnFibonacci(int a) {

  double firstTerm; // calculate h

  double secondTerm; //calculate j

  double fib; //calculate 1/sqrt(5) with firstTerm and secondTerm

}