java - 我没有让循环在每次循环后获取新值？

Question

我正在尝试解决一个问题，即我尝试让循环在每次循环后采用新值。该程序应该对我的利息支付、本金支付和当前余额进行罚款，这样做，每次我循环时，我的利息应该会越来越少，但它只会循环第一个答案超过

这是输出，第一个答案是正确的，但其他三个答案是正确的

    Enter Loan Amount:500
    Enter Annual Interest:50
    Total payment:4
    Enter Loan Length :1
    Interest PaymentPrincipal PaymentCurrent Balance
    Interest Payment Principal Payment Current Balance 62.5
    62.5
    62.5
    62.5

应该是第一次付款后余额的 12.5%。

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        //variabled decleared
        double rate;
        double payment;
        int amt = 1;
       //input
       System.out.print("Enter Loan Amount:");
        double principal = input.nextDouble();
        System.out.print("Enter Annual Interest:");
        double interest = input.nextDouble();
        System.out.print("Total payment:");//12=monthly,4= quartely,2=semi-annually and 1=annually
        double period = input.nextDouble();
        System.out.print("Enter Loan Length :");
        int length = input.nextInt();

        //proces
        rate = interest / 100;
        double period_rate = rate / period;
          double n = period * length;
        payment = (principal*Math.pow((1+period_rate),n))/n;





        System.out.printf("\n"+"Interest Payment"+"     Principal Payment       "+"         Current Balance     ");

        for(int i=1; i<=n; i++){
        double principal_payment=0;
        double current_balance;
        double payment_interest;

        current_balance=(principal-principal_payment);
         payment_interest=(principal*period_rate);
        principal_payment=(payment-payment_interest);
        principal=current_balance;



         System.out.println(payment_interest+"");

         }

Answer 1

忘掉编程吧。拿起铅笔和纸，花几个月的时间进行计算。然后将这些计算转移到代码中。当你在了解问题所在之前就开始编码，你就有点超前了。