import java.util.Scanner;public class compounding {    public static void main(String[] args) {        menu();        int m = scanner.nextInt();        switch(m)        {        case 1:            compound_calate(); break;        case 2:            single_calate();break;        }              }    private static void compound_calate() {
   //复利计算                while (true) {            System.out.println("");                        menu1();            int n = scanner.nextInt();            if (n >= 0 && n <= 6) {                if (n == 0)                    System.exit(0);                switch (n) {                case 1:                    principal();                    break;                             case 2:                     compound_final();                    break;                case 3:                    time();                    break;                            case 4:                    annual_interest_rate();                    break;                case 5:                    equal_investment();                    break;                case 6:                    Average_repayment();                    break;                               }            } else {                System.out.println("输入超出范围，请重新输入:");            }        }    }        static Scanner scanner = new Scanner(System.in);    static void menu()// 功能介绍函数    {        System.out.printf("\t\t|******************************************************|\n");        System.out.printf("\t\t|                     利息计算系统                                                            |\n");        System.out.printf("\t\t|******************************************************|\n");        System.out.printf("\t\t|                    1: 复利计算                                                              |\n");        System.out.printf("\t\t|                    2: 单利计算                                                              |\n");        System.out.printf("\t\t|******************************************************|\n");        System.out.printf("\t请选择<1~2>:");    }    static void menu1()// 菜单    {        System.out.printf("\t\t|******************************************************|\n");        System.out.printf("\t\t|                    1: 本金计算                                                                |\n");        System.out.printf("\t\t|                    2: 终值计算                                                               |\n");        System.out.printf("\t\t|                    3: 期数计算                                                               |\n");        System.out.printf("\t\t|                    4: 利率计算                                                               |\n");        System.out.printf("\t\t|                    5: 定期计算                                                               |\n");        System.out.printf("\t\t|                    6: 等额本息还款                                                       |\n");        System.out.printf("\t\t|******************************************************|\n");        System.out.printf("请输入你要选择的功能(1~6):");    }    static double principal_formula(double S, double i, int Year)// 本金计算公式    {        double P;        P = S/ Math.pow((1 + i ), Year);        return P;    }    static void principal()// 计算本金    {        int Year;        double i,P,S;        System.out.printf("输入期待复利终值:");        S = scanner.nextDouble();        System.out.printf("年利率:");        i = scanner.nextDouble();        System.out.printf("存入年限:");        Year = scanner.nextInt();            P = principal_formula(S, i, Year);        System.out.println("年复利终值为" + S + "需要本金为:" + P);    }    static double compound_amount_formula(double P, double i, int Year)// 复利计算公式    {        double F;        F = P * Math.pow((1 + i ),Year);        return F;    }    static void compound_final()// 计算复利终值    {        int Year;        double i, F, P;        System.out.printf("请输入本金：");        P = scanner.nextDouble();        System.out.printf("请输入年利率：");        i = scanner.nextDouble();        System.out.printf("请输入复利次数（年）：");        Year = scanner.nextInt();        F = compound_amount_formula(P, i, Year);        System.out.println("复利终值:" + F);    }    static double single_interest_formula(double P, int Year, double i)// 单利计算公式    {        double F;        F = P *(1+i*Year);        return F;    }    static void single_calate()// 单利计算    {        int Year;        double i, F, P;        System.out.printf("存入本金:");        P = scanner.nextDouble();        System.out.printf("年利率:");        i = scanner.nextDouble();        System.out.printf("存入年限:");        Year = scanner.nextInt();        F = single_interest_formula(P, Year, i);        System.out.println("本息和为:" + F);    }    static int years_formula(double F, double P, double i)// 根据复利终值求年份    {        int year;        year = (int) (Math.log(F / P) / Math.log(1 + i ));        return year;    }    static void time()// 求年份    {        int Year;        double i, F, P;        System.out.printf("复利终值:");        F = scanner.nextDouble();        System.out.printf("存入本金:");        P = scanner.nextDouble();        System.out.printf("年利率:");        i = scanner.nextDouble();        Year= years_formula(F, P, i);        System.out.println("从" + P + "到" + F + "需要" + Year+ "年");    }    static double rate_formula(double F, double P, int Year)// 复利的利率计算公式    {        double rate;        rate = (Math.pow(F / P, 1.0 / Year) - 1);        return rate;    }    static void annual_interest_rate()// 计算年利率    {        int Year;        double i, F, P;        System.out.printf("复利终值:");        F = scanner.nextDouble();        System.out.printf("存入本金:");        P = scanner.nextDouble();        System.out.printf("存入年限:");        Year = scanner.nextInt();        i = rate_formula(F, P, Year);        System.out.println("从" + P + "到" + F + "需要" + i);    }    static double equal_investment_years(double P, int Year, double i)// 按照年份等额投资计算公式    {        double final_value;        final_value = P * (Math.pow(1 + i, Year) - 1) / i;        return final_value;    }    static double equal_investment_months(double P, int Year, double i)// 按照月份等额投资计算公式    {        double final_value;        final_value = P * 12 * (1 + i) * (Math.pow(1 + i, Year) - 1) / i;        return final_value;    }    static void equal_investment()// 计算等额投资    {        int Year, n;        double i, F, P;        System.out.printf("\t\t1:按年投资\n\t\t2:按月投资\n");        System.out.printf("请选择你要的功能<1|2>:");        n = scanner.nextInt();        if (n == 1) {            System.out.printf("存入本金:");            P = scanner.nextDouble();            System.out.printf("存入年限:");            Year = scanner.nextInt();            System.out.printf("年利率:");            i = scanner.nextDouble();            F = equal_investment_years(P, Year, i);            System.out.println(Year+ "年后的总产值:" + F);        } else if (n == 2) {            System.out.printf("存入本金:");            P = scanner.nextDouble();            System.out.printf("存入年限:");            Year = scanner.nextInt();            System.out.printf("月利率:");            i = scanner.nextDouble();            F = equal_investment_months(P, Year, i);            System.out.println(Year + "年后的总产值:" + F);        } else {            System.out.printf("输入有误!\n");        }    }    static double equal_repayment_formula(double F, int Year,double i)// 等额还款公式    {        double refund;        refund = F * i / (12 * (1 + i) * (Math.pow(1 + i, Year) - 1));        return refund;    }    static void Average_repayment()// 等额还款    {        int Year;        double i, F, P;        System.out.printf("贷款金额:");        F = scanner.nextDouble();        System.out.printf("存入年限:");        Year = scanner.nextInt();        System.out.printf("年利率:");        i = scanner.nextDouble();        P = equal_repayment_formula(F, Year, i);        System.out.println("贷款" + F + "每月需要还款" + P);    }}