年度贡献的Java复合利息计算器

如何解决年度贡献的Java复合利息计算器

我正在尝试创建一个计算年度复利加上额外年度供款的程序。当我的供款= 0时，我的输出正确地计算了新的余额，但是当我改变供款时，输出错误了。

    Scanner input1 = new Scanner(System.in);

    double amount;
    
    System.out.print("Enter starting year: ");
    Scanner input2 = new Scanner (System.in);
    
    System.out.print("Enter starting balance: ");
    Double principal = input1.nextDouble();

    System.out.print("Enter additional annual contribution: ");
    Double contribution = input1.nextDouble();

    System.out.print("Enter annual growth rate: ");
    Double rate = input1.nextDouble();
    Double rateDec = rate / 100

    for(int year = 1; year <= 21; year++){
        amount = (principal * Math.pow(1 + rateDec,year)) ;
        Double addedamount = amount + contribution;
        System.out.println(year + "  " + addedamount);

    }           
    

我的输出是这个

Principle = 10000
rate = 9.69

贡献= 600

1  11569.0
2  12631.8961
3  13797.78683209
4  15076.65237611952
5  16479.439991365503
6  18018.157726528818
7  19705.977210229463
8  21557.346401900697
9  23588.113268244873
10  25815.6614439378
11  28259.05903785537
12  30939.221858623558
13  33879.09245672418
14  37103.83651578075
15  40641.05827415991
16  44521.036820926
17  48776.98528887373
18  53445.3351633656
19  58566.04814069572
20  64182.95820552914
21  70344.14685564491

但应该是

1  11,569.00 
2  13,290.04 
3  15,177.84 
4  17,248.57 
5  19,519.96 
6  22,011.44 
7  24,744.35 
8  27,742.08 
9  31,030.29 
10 34,637.12 
11 38,593.46 
12 42,933.17 
13 47,693.39 
14 52,914.88 
15 58,642.33 
16 64,924.77 
17 71,815.99 
18 79,374.95 
19 87,666.39 
20 96,761.26

解决方法

我无法完全理解您的问题，但您似乎想每年计算出有贡献的复利。我认为从第一年开始的每年的开始，每年都会进行捐款。

此外，下次您询问时，请检查Stackoverflow How to Ask。它提供了更好的可读性

据我了解：

public static void main(String[] args) {
    
    double contribution = 600; //Yearly contribution
    double initialAmount = 10000; 
    double rateOfInterest = 9.69; //9.96% per anum
    double years = 10;

    double rateFactor = 1 + rateOfInterest/100; //Rate factor = 1.969 if rate is 10%

    //Final calculation Assuming contribution is made on first day of year including first year also
    double finalAmount = initialAmount;
    for(int year=0; year<years; year++){
        System.out.println(year+" "+finalAmount+" "+contribution);
        
        finalAmount = finalAmount*rateFactor;
        finalAmount += contribution;
    }   
    
    System.out.println("Final Amount: "+finalAmount);
}

其输出将是：

0 10000.0 600.0
1 11569.0 600.0
2 13290.0361 600.0
3 15177.840598089999 600.0
4 17248.57335204492 600.0
5 19519.960109858075 600.0
6 22011.444244503324 600.0
7 24744.353191795697 600.0
8 27742.0810160807 600.0
9 31030.28866653892 600.0
10 34637.12363832654 600.0
11 38593.46091888038 600.0
12 42933.16728191989 600.0
13 47693.39119153792 600.0
14 52914.88079799795 600.0
15 58642.33274732395 600.0
16 64924.77479053964 600.0
17 71815.98546774292 600.0
18 79374.95445956722 600.0
19 87666.38754669928 600.0
Final Amount: 96761.26049997444

PS：：如果您不理解上面的代码，并且想更清楚地了解上面的计算方法。您应该在任何网站的Aptitude的“复利”部分中进行更多练习。