0321复利计算4.0

import java.util.Scanner;

public class text {

    public static void main(String[] args) {
        while (true) {
            Scanner scanner = new Scanner(System.in);
            System.out.println("----------------------------");
            System.out.println("    1.算本息                          ");
            System.out.println("    2.算本金                          ");
            System.out.println("    3.算投资年限或年利率      ");
            System.out.println("    4.定投收益                       ");
            System.out.println("    5.每月等额本息还款          ");
            System.out.println("    0.退出                             ");
            System.out.println("----------------------------");
            System.out.print("请选择：");
            int number = scanner.nextInt();
            switch (number) {
            case 1:
                Benxi();
                break;
            case 2:
                Benjin();
                break;
            case 3:
                Touzi();
                break;
            case 4:
                Dingtoushouyi();
                break;
            case 5:
                Dengerbenxihuanknan();
                break;
            case 0:
                Exit();
                break;
            default: {
                System.out.println("输入错误!请重新输入!");
                break;
            }
            }
        }

    }

    private static void Exit() {
        // TODO 自动生成的方法存根
        System.out.println("谢谢使用！");
        System.exit(0);

    }

    private static void Dengerbenxihuanknan() {
        // TODO 自动生成的方法存根
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入贷款本金：");
        double money = scanner.nextDouble();
        System.out.print("请输入年利率：");
        double rate = scanner.nextDouble();
        System.out.print("请输入年限：");
        int year = scanner.nextInt();
        double num = 1;
        for (int i = 1; i <= year * 12; i++) {
            num = (1 + (rate / 12)) * num;

        }
        money = money * ((rate / 12) * num) / (num - 1);
        System.out.println("每月等额本息还款："
                + (double) (Math.round(money * 100) / 100.0));

    }

    private static void Dingtoushouyi() {
        // TODO 自动生成的方法存根
        Scanner scanner = new Scanner(System.in);

        System.out.print("请选择（1为每年定投，2为每月定投）：");
        int number2 = scanner.nextInt();
        if (number2 == 1) {
            System.out.print("请输入每年的投资金额：");
            double money = scanner.nextDouble();
            System.out.print("请输入年利率：");
            double rate = scanner.nextDouble();
            System.out.print("请输入年限：");
            int year = scanner.nextInt();
            double num = 1;
            for (int i = 1; i <= year; i++) {
                num = (1 + rate) * num;

            }
            money = money * (1 + rate) * (-1 + num) / rate;
            System.out.println("定投" + year + "年后的资产总值为："
                    + (double) (Math.round(money * 100) / 100.0));
        } else if (number2 == 2) {
            System.out.print("请输入每月的定投金额：");
            double money = scanner.nextDouble();
            System.out.print("请输入年利率：");
            double rate = scanner.nextDouble();
            System.out.print("请输入年限：");
            int year = scanner.nextInt();
            double num = 1;
            for (int i = 1; i <= year * 12; i++) {
                num = (1 + (rate / 12)) * num;

            }
            money = money * (1 + (rate / 12)) * (-1 + num) / (rate / 12);
            System.out.println("定投" + year + "年后的资产总值为："
                    + (double) (Math.round(money * 100) / 100.0));

        }

    }

    private static void Touzi() {
        // TODO 自动生成的方法存根
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入投资金额：");
        double money1 = scanner.nextDouble();
        System.out.print("请输入收获金额：");
        double money2 = scanner.nextDouble();

        System.out.print("请选择（1为算时间，2为算利率）：");
        int number2 = scanner.nextInt();

        if (number2 == 1) {
            System.out.print("请输入年利率：");
            double rate = scanner.nextDouble();
            double year;
            year = Logarithm.log(money2 / money1, 1 + rate);
            year = Math.ceil(year);
            System.out.println("需要存入的年限为：" + year);
        } else if (number2 == 2) {
            System.out.print("请输入年限：");
            int year = scanner.nextInt();
            double rate;
            rate = Math.pow(money2 / money1, 1.0 / year) - 1;
            System.out.println("所需年利率为："
                    + (double) (Math.round(rate * 10000) / 10000.0));

        }

    }

    private static void Benjin() {
        // TODO 自动生成的方法存根
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入本息：");
        double money = scanner.nextDouble();
        System.out.print("请输入年利率：");
        double rate = scanner.nextDouble();
        System.out.print("请输入年限：");
        int year = scanner.nextInt();

        System.out.print("请选择（1为复利计算，2为单利计算）：");
        int number2 = scanner.nextInt();

        if (number2 == 1) {
            double num = 1;
            for (int i = 1; i <= year; i++) {
                num = num * (1 + rate);
            }
            money = money * (1 / num);
            System.out.println("复利计算需要存入的本金为："
                    + (double) (Math.round(money * 100) / 100.0));
        }
        if (number2 == 2) {
            money = money * (1 / (1 + rate * year));
            System.out.println("单利计算需要存入的本金为："
                    + (double) (Math.round(money * 100) / 100.0));

        }

    }

    private static void Benxi() {
        // TODO 自动生成的方法存根
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入本金：");
        double money = scanner.nextDouble();
        System.out.print("请输入年利率：");
        double rate = scanner.nextDouble();
        System.out.print("请输入年限：");
        int year = scanner.nextInt();

        System.out.print("请选择（1为复利计算，2为单利计算）：");
        int number2 = scanner.nextInt();

        if (number2 == 1) {
            for (int i = 1; i <= year; i++) {
                money = (1 + rate) * money;
            }
            System.out.println("存入" + year + "年后的复利计算本息为："
                    + (double) (Math.round(money * 100) / 100.0));

        }
        if (number2 == 2) {
            money = money + money * rate * year;
            System.out.println("存入" + year + "年后的单利计算本息为："
                    + (double) (Math.round(money * 100) / 100.0));

        }

    }
}

public class Logarithm {
    static public double log(double value, double base){
        return Math.log(value)/Math.log(base);
         
     }

}