斐波那契最后的数字

Question

我已经完成了这部分代码，我正在尝试让它只打印最后一个斐波那契数列，而不是全部。我应该怎么做呢？我知道整个程序还没有完成，但我只需要知道如何打印最后一个数字，例如，当你 select 选择 1，然后输入“30”作为索引时，你应该只会得到一个输出832040 而不是每个斐波那契数到 30。谢谢！

import java.util.Scanner;

public class Fibonacci {

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

    System.out.println("This is a Fibonacci sequence generator");
    System.out.println("Choose what you would like to do");
    System.out.println("1. Find the nth Fibonacci number");
    System.out.println("2. Find the smallest Fibonacci number that exceeds user given value");
    System.out.println("3. Find the two Fibonacci numbers whose ratio is close enough to the golden number");

    System.out.print("Enter your choice: ");
    int choice = scan.nextInt();
    int xPre = 0;
    int xCurr = 1;
    int xNew;

    switch (choice)
    {
        case 1:
            System.out.print("Enter the target index to generate (>1): ");
            int index = scan.nextInt();

            for (int i = 2; i<=index; i++)
            {xNew = xPre + xCurr;
            xPre = xCurr;
            xCurr = xNew;
        System.out.println("The " + index + "th number Fibonacci number is " + xNew);

} 
}}}

Answer 1

基本上修改代码如下

switch (choice)
{
    case 1:
        System.out.print("Enter the target index to generate (>1): ");
        int index = scan.nextInt();

        for (int i = 2; i<=index; i++)
        {xNew = xPre + xCurr;
        xPre = xCurr;
        xCurr = xNew;       
} 
System.out.println("The " + index + "th number Fibonacci number is " + xNew);

由于 xNew 变量最后被修改为保存索引值（例如 - 30），因此它应该单独显示最终值 832040。

斐波那契最后的数字

Fibonacci Last Number

fibonacci