Question

我试图编写一个递归方法，该方法需要3个参数（贷款金额，利率和每月付款）。利息每月复利。目标是找出完全还清贷款需要多少个月。这是我到目前为止的代码：

    public static double loanLength(double loan, double interest, double payment) {
    if (payment > loan + loan * interest) {
        return 0;
    } else {
        double completeLoan = loan + (loan * interest);
        double stillOwe = completeLoan - payment;
        if (stillOwe <= 0) {
            return 1;
        } else {
            return 1 + (loanLength(stillOwe, interest, payment));
        }

    }

EXPECTED返回的示例包括：

loanLength（1000,0.10,200）在6个月内还清

loanLength（0,0.90,50）为0个月

但我的回报如下：

loanLength（1000,0.10,200）：7个月

loanLength（0,0.90,50）：0个月

我的第二个测试工作正常，但我的第一个测试只比它应该的1个整数。我无法弄清楚为什么。任何帮助表示赞赏。

Answer 1

public static int loanLength(double loan, double interestAPR, double payment) {
    if (loan <= 0) {
        return 0;
    }
    double monthlyInterest = interestAPR / (12 * 100);
    double compounded = loan * (1 + monthlyInterest);
    return 1 + loanLength(compounded - payment, interestAPR, payment);
}

public static void main(String[] args) {
    System.out.println(loanLength(0, 0.90, 50)); // 0
    System.out.println(loanLength(1000, 10.0, 200)); // 6
    System.out.println(loanLength(1000, 0.1, 200)); // 6 (FWIW)
}

请注意，利息APR按表示，即10％年利率的10,000美元贷款和每月500美元的付款计算为

loanLength(10000, 10.0, 500);

如果0.10 = 10％APR，则更改此行

double monthlyInterest = interestAPR / 12;

贷款计算的递归方法

1 个答案: