0320复利计算5

7. 你写的程序能让客户随意操作吗？误输入数据、不小心做了非常规的操作程序是什么反应？ 

    相互观赏程序运行情况。

8. 如果向银行贷款10万元，年利率6.5%，期限为10年，那么每月等额本息还款多少？（算复利条件下等额还款金额）

package bin;

import java.util.Scanner;

public class compounding {


    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner s=new Scanner(System.in);
        System.out.println("1.复利计算   2.单利计算  3.总额反向计算本金  4.买股票算年份  5.本金终值求利率  6.每年都投入本金  7.贷款");
        int num=s.nextInt();
        
            switch(num){
                case 1:
                    one(s);
                    break;
                case 2:
                    two(s);
                    break;
                case 3:
                    three(s);
                    break;
                case 4:
                    four(s);
                    break;
                case 5:
                    five(s);
                    break;
                case 6:
                    System.out.println("请选择 1.按年定投  2.按月定投:");
                    int six=s.nextInt();
                    if(six==1)
                        six1(s);
                    else
                        six2(s);
                    break;
                case 7:
                    seven(s);
                    break;
                default:
                    System.out.println("输入有误");
                    break;
        }
        
    }

    private static void five(Scanner s) {
        double sum=0;
        System.out.println("请输入本金：");
        double startmoney=s.nextDouble();
        System.out.println("请输入终值:");
        double endmoney=s.nextDouble();
        System.out.println("请输入年数:");
        double years=s.nextInt();
        double r=Math.pow((endmoney/startmoney), 1/years)-1;
        System.out.println(r);
    }

    private static void four(Scanner s) {
        double sum=0;
        System.out.println("请输入本金：");
        double startmoney=s.nextDouble();
        System.out.println("请输入终值:");
        double endmoney=s.nextDouble();
        System.out.println("请输入利率:");
        double r=s.nextDouble();
        double years=Math.log(endmoney/startmoney)/Math.log(1+r);
        System.out.println("存入"+startmoney+"每年按"+r+"利率最终获得"+endmoney+"需要"+years);
    }

    private static void three(Scanner s) {
        double sum=0;
        System.out.println("请输入终值：");
        double money=s.nextDouble();
        System.out.println("请输入年数:");
        int years=s.nextInt();
        System.out.println("请输入利率:");
        double r=s.nextDouble();
        double Single=money/(1+years*r);
        double Double=money/(Math.pow((1+r),years));
        System.out.println("单利现值为:"+Single);
        System.out.println("复利现值为:"+Double);
    }

    private static void two(Scanner s) {
        double sum=0;
        System.out.println("请输入本金：");
        double money=s.nextDouble();
        System.out.println("请输入年数:");
        int years=s.nextInt();
        System.out.println("请输入利率:");
        double r=s.nextDouble();
        sum=money*r*years;
        System.out.println("单利计算"+years+"年后总额为:"+(sum+money));
    }

    private static void one(Scanner s) {
        double sum=0;
        System.out.println("请输入本金：");
        double money=s.nextDouble();
        System.out.println("请输入年数:");
        int years=s.nextInt();
        System.out.println("请输入利率:");
        double r=s.nextDouble();

        sum=money*Math.pow(1+r, years);
        System.out.println(years+"年后总额为"+sum);
    }
    
    private static void six1(Scanner s){
        double sum=0;
        System.out.println("请输入每年投入本金：");
        double money=s.nextDouble();
        System.out.println("请输入年数:");
        int years=s.nextInt();
        System.out.println("请输入利率:");
        double r=s.nextDouble();
        sum=money*(1+r)*(-1+Math.pow(1+r, years))/r;

        System.out.println("年后总额为"+sum);
    }
    private static void six2(Scanner s){
        double sum=0;
        System.out.println("请输入每月投入本金：");
        double money=s.nextDouble();
        System.out.println("请输入年数:");
        int years=s.nextInt();
        System.out.println("请输入利率:");
        double r=s.nextDouble();
        sum=money*12*(1+r)*(-1+Math.pow(1+r, years))/r;
        System.out.println("年后总额为"+sum);
    }
    
    private static void seven(Scanner s) {
        double sum=0;
        System.out.println("请输入本金：");
        double money=s.nextDouble();
        System.out.println("请输入年数:");
        int years=s.nextInt();
        System.out.println("请输入利率:");
        double r=s.nextDouble();
        sum=money*Math.pow(1+r, years);
        double monthMoney=sum/years/12;
        System.out.println("每月还的本息金额为："+monthMoney);
    }
    
    

}