public class a1 {public static void main(String[] args) {Tool t1 = new Tool();int day = 1;int peachNum = t1.peach(day);if (peachNum == -1) {System.out.println("天数不正确");}else {System.out.println("第" + day + "天的桃子数为 " + peachNum);}}
}
class Tool {public int peach(int day) {if (day == 10) {return 1;}else if (day > 0 && day < 10) {return (peach(day + 1) + 1) * 2;}else {return -1;}}
}

import java.util.Scanner;
public class a1 {public static void main(String[] args) {Scanner myScanner = new Scanner(System.in);Tool t1 = new Tool();System.out.println("请输入猴子吃桃一共经过的天数");int totalDay = myScanner.nextInt();System.out.println("请输入要查询的桃子数的天数");int day = myScanner.nextInt();int peachNum = t1.peach(totalDay, day);if (peachNum == -1) {System.out.println("天数不正确");}else {System.out.println("第" + day + "天的桃子数为 " + peachNum);}}
}
class Tool {public int peach(int totalDay, int day) {if (day == totalDay) {return 1;}else if (day > 0 && day < totalDay) {return (peach(totalDay, day + 1) + 1) * 2;}else {return -1;}}
}