JavaDay05.练习1

键盘输入一个数字和个数,输出结果如下
比如输入一个2,然后输入一个5
则打印出:
2+22+222+2222+22222=?
?号为累加的结果

import java.util.Scanner;

public class Homework {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请您输入起始数字: ");
        int num = scanner.nextInt();
        System.out.println("请您输入需要的个数: ");
        int count = scanner.nextInt();
        //创建数组,长度为输入的项数
        int[] arr = new int[count];
        //赋值数组第一个元素
        arr[0] = num;
        int i = 1;
        //循环把每个值赋值到数组中
        while (i < count) {
            num *= 10;
            arr[i] = num + arr[i - 1];
            i++;
        }
        //求和
        long sum = 0;
        for (int j = 0; j < arr.length; j++) {
            System.out.print(j == arr.length - 1 ? arr[j] + "=" : arr[j] + "+");
            sum += arr[j];
        }
        System.out.println(sum);
    }
}