Compound Interest Calculator3.0
1.利率这么低，复利计算收益都这么厉害了，如果拿100万元去买年报酬率10%的股票，若一切顺利，过多长时间，100万元就变成200万元呢？
2.如果我希望在十年内将100万元变成200万元，应该找到报酬率在多少的投资工具来帮助我达成目标？如果想在5年后本金翻倍，报酬率就应至少为多少才行呢？
3.如果每年都将积蓄的3万元进行投资，每年都能获得3%的回报，然后将这些本利之和连同年金再投入新一轮的投资，那么，30年后资产总值将变为多少？如果换成每月定投3000呢？
import java.util.Scanner;
public class Calculator3 {
public static void main(String[] args) {
// TODO 自动生成的方法存根
Scanner scanner = new Scanner(System.in);
int key=0;
while (key == 0 || key == 1 || key == 2 || key==3 || key==4 || key==5) {
System.out.println("欢迎使用" + "\n计算单利和复利终值，请按1" + "\n计算本金，请按2"
+ "\n股票投资，请按3"
+ "\n计算利率，请按4"
+ "\n计算资产总值，请按5"
+ "\n请输入：");
int key1 = scanner.nextInt();
if (key1 == 1) {
Calculator3.DanliandFuli(); // 计算单利和复利
break;
} else if (key1 == 2) {
Calculator3.Principal(); // 计算本金
break;
} else if (key1 == 3) {
Calculator3.Stock(); // 股票投资(计算时间)
break;
} else if (key1 == 4) {
Calculator3.Rate(); // 计算利率
break;
} else if (key1 == 5) {
Calculator3.Assets(); // 计算资产总值
break;
}else {
System.out.println("\n输入错误！！！");
}
}
}
private static void DanliandFuli() {
// TODO 自动生成的方法存根
double N = 1, sum;
Scanner scanner = new Scanner(System.in);
System.out.println("请输入本金：");
double money = scanner.nextDouble();
System.out.println("请输入存钱年数：");
int years = scanner.nextInt();
System.out.println("请输入年利率：");
double rate = scanner.nextDouble();
sum=money+money*years*rate;
System.out.println("单利计算值为：" + sum);
sum=0;
for (int i = 1; i <= years; i++) {
N = (1 + rate) * N;
}
sum = N * money;
System.out.println("复利计算值为：" + sum);
}
private static void Principal() {
// TODO 自动生成的方法存根
double N = 1, money;
Scanner scanner = new Scanner(System.in);
System.out.println("请输入复利终值：");
double sum = scanner.nextDouble();
System.out.println("请输入存钱年数：");
int years = scanner.nextInt();
System.out.println("请输入年利率：");
double rate = scanner.nextDouble();
for (int i = 1; i <= years; i++) {
N = (1 + rate) * N;
}
money = sum / N;
System.out.println("应投入的本金为：" + money);
}
private static void Stock() {
// TODO 自动生成的方法存根
Scanner scanner = new Scanner(System.in);
System.out.println("请输入本金：");
double money = scanner.nextDouble();
System.out.println("请输入复利终值：");
int sum = scanner.nextInt();
System.out.println("请输入年利率：");
double rate = scanner.nextDouble();
int years=(int) ((Math.log(sum)/Math.log(1+rate))-(Math.log(money)/Math.log(1+rate)));
System.out.println("所需年限为：" + years);
}
private static void Rate() {
// TODO 自动生成的方法存根
double rate;
Scanner scanner = new Scanner(System.in);
System.out.print("请输入本金：");
double money = scanner.nextDouble();
System.out.print("请输入最后得到资产总值：");
double sum = scanner.nextDouble();
System.out.print("请输入存钱年数：");
int years = scanner.nextInt();
rate=sum/(money*years);
System.out.println("利率为：" + rate);
}
private static void Assets() {
// TODO 自动生成的方法存根
double sum;
Scanner scanner = new Scanner(System.in);
System.out.print("请输入本金：");
double money = scanner.nextDouble();
System.out.print("请输入利率：");
double rate = scanner.nextDouble();
System.out.print("请输入存钱年数：");
int years = scanner.nextInt();
sum=money*rate*years;
System.out.println("若投资本金每年固定不变，最后得到的资产总值为：" + sum);
sum=0;
for(int i=1;i<=years;i++){
sum=money*rate*1;
money=sum;
}
System.out.println("若连本带利投资，最后得到的资产总值为：" + sum);
}
}
演算结果：