复利计算器（软件工程）及Junit测试———郭志豪

package FuLi;

import java.util.*;
import java.math.*;
import java.text.*;

import org.omg.CORBA.PUBLIC_MEMBER;

public class gzh {

public int NianXian(double P,double F,double i){

int N=(int) ((Math.log(F) / Math.log(1 + i)) - (Math.log(P) / Math
.log(1 + i)));
return N;

}

public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("欢迎使用复利计算器！--BY 郭志豪");
/*
* 复利计算公式: F=P*(1+i)N(次方) 　　 F：复利终值 　　 P：本金 　　 i：利率 　　 N：利率获取时间的整数倍
*/
gzh bb = new gzh();
Scanner input = new Scanner(System.in);
System.out.println("复利计算器：");
System.out.println("本金按1 复利(单利)按2 年限按3 利率按4 年金终值按5 定期付息按6");
int num = input.nextInt();
DecimalFormat df1 = new DecimalFormat("#.00");
// 求本金

if (num == 1) {
System.out.println("请输入复利终值：");
double F = input.nextDouble();
System.out.println("请输入年利率:");
double i = input.nextDouble();
System.out.println("请输入存入年限:");
int N = input.nextInt();
double P = F / Math.pow(1 + i, N); // 本金
System.out.println("所需本金为：" + df1.format(P));
}
// 求复利（单利）
else if (num == 2) {
System.out.println("请输入存入本金:");
double P = input.nextDouble();
System.out.println("请输入年利率:");
double i = input.nextDouble();
System.out.println("请输入存入年限:");
int N = input.nextInt();
double D = P * (1 + i * N); // 单利
System.out.println("单利终值：" + df1.format(D));
System.out.println("请输入年复利次数：");
int m = input.nextInt();
double F = P * (Math.pow((1 + i / m), N * m)); // 复利
System.out.println("复利终值为:" + df1.format(F));
}
// 求所需年限
else if (num == 3) {
System.out.println("请输入存入本金:");
double P = input.nextDouble();
System.out.println("请输入复利终值：");
double F = input.nextDouble();
System.out.println("请输入年利率:");
double i = input.nextDouble();
int N1 = (int)bb.NianXian(F, i, P);
//int N = (int) ((Math.log(F) / Math.log(1 + i)) - (Math.log(P) / Math
// .log(1 + i)));
System.out.println("所需年限为:" +N1);
} else if (num == 4) {
System.out.println("请输入存入本金:");
double P = input.nextDouble();
System.out.println("请输入复利终值：");
double F = input.nextDouble();
System.out.println("请输入存入年限:");
int N = input.nextInt();
double i = (Math.pow(F / P, 1.0 / N)) - 1;
System.out.println("年利率为：" + i);
System.out.println("本金n年后是否会翻n番？是请按1");
int up = input.nextInt();
if (up == 1) {
System.out.println("请输入几年后：");
int n = input.nextInt();
System.out.println("翻几番：");
int f = input.nextInt();
double I = 72.0 / (n / f); // 72法则
System.out.println(n + "年后本金翻倍的年利率至少为：" + df1.format(I));
}
if (up != 1) {
System.out.println("欢迎再来！");

}
} else if (num == 5) {
System.out.println("按年投资按1 按月投资按2 ");
int number = input.nextInt();
if (number == 1) {
System.out.println("要投资的本金：");
double P = input.nextDouble();
System.out.println("获得的年利率回报：");
double i = input.nextDouble();
System.out.println("投资年限(年)：");
double N = input.nextInt();

double F = P * (Math.pow(1 + i, N) - 1) / i;
System.out.println("按年投资的年金终值为：" + df1.format(F));
}
if (number == 2) {
System.out.println("要投资的本金：");
double P = input.nextDouble();
System.out.println("获得的年利率回报：");
double i = input.nextDouble();
System.out.println("投资年限(年)：");
double N = input.nextInt();
double F = P * (Math.pow(1 + i / 12.0, N * 12) - 1) / (i / 12);
System.out.println("按月投资的年金终值为：" + df1.format(F));
}
if (number != 1 || number != 2) {
System.out.println("输入错误！");
}
} else if (num == 6) {
System.out.println("要贷款的本金：");
double P = input.nextDouble();
System.out.println("贷款年利率：(年)");
double i = input.nextDouble();
System.out.println("贷款期(年)：");
double N = input.nextDouble();
double H = P
* (((i / 12) * (Math.pow(1 + i / 12, N * 12))) / (Math.pow(
1 + i / 12, N * 12) - 1));
System.out.println("需每月还款：" + df1.format(H));
} else {
System.out.println("输入错误！");
}
}

}