水仙花数等

import java.util.*;
public class Sum{
	public static void main(String [] args){
		double divisor = 1;
		double div = 3;
		double sum = 0;
		while(div <= 99){
			sum = sum + divisor / div;
			div += 2;
		}
		System.out.printf("结果为：%.2f",sum);
		System.out.println();
		
		System.out.println("1.**************************");
		//输出所有的三位水仙花数
		int num = 100;
		int a;
		int b;
		int c;
		while(num < 1000){
			a = num % 10;
			b = num / 10 % 10;
			c = num / 100 % 10;
			if(a*a*a + b*b*b + c*c*c == num){
				System.out.println(num+" 是水仙花数");
			}
			num ++;
		}
		
		System.out.println("2.**************************");
		//利用for循环 1/2+2/3+3/5+5/8+8/13+……求前10项之和
		int x = 1;
		int y = 2;
		int temp = 0;
		double sum2 = 0;
		for(int i = 0 ; i < 10 ; i++){
			sum2 += 1.0* x / y;
			temp = y;
			y += x;
			x = temp;
		}
		System.out.printf("前10项之和为：%.2f",sum2);
		
		System.out.println();
		System.out.println("3.**************************");
		//利用for循环，输入两个数比如2 5，计算2+22+222+2222+22222的结果
		System.out.println("分别输入一个数字和运算次数：");
		Scanner sc = new Scanner(System.in);
		int f = sc.nextInt();
		int time = sc.nextInt();
		int first = f;
		int sum3 = 0;
		for(int i = 0; i < time; i++){
			System.out.println(first);
			sum3 += first;
			first = first*10 + f;  
		}
		System.out.println("结果为："+sum3);
		
		
	}
}