java - 贷款复利计算器java

Question

double a = Double.parseDouble(amount.getText());
double r = Double.parseDouble(rate.getText())/100;
double y = Double.parseDouble(years.getText());
double m=y*12;
double simple =a+(a*r*y);
double compound = a * Math.pow(1+ r, m);
String d = String.format("%.2f", simple);
String d1 = String.format("%.2f", simple/12);
String d2 = String.format("%.2f", compound);
int x=1;

while(x<=m && type.getSelectedItem().equals("Simple")) {
     monthly1.append(String.valueOf(x+(". ")+d1+("\n"))); 
     x++;
     total1.setText(String.valueOf(d));
}

if (type.getSelectedItem().equals("Compound")){
    for (int month=1;month<=m;month++){
       monthly2.append(String.valueOf(month+(". ")+d2+"\n"));
       total2.setText(String.valueOf(d2));
     } 
}

单利可以，但月复利不行。我试过了

amount:1000 rate:5 years 3.

得到了

1. 5791.82
2. 5791.82
3. 5791.82

up to 60.

我希望它显示我每月必须支付的费用。

Answer 1

您似乎只在代码的最开始计算compound一次。我将创建一个方法calculateCompoundInterest(int Month)，然后从循环中调用它，如下所示:

for (int month=1; month <= m; month++) {
    String monthlyAmount = String.format("%.2f", calculateCompoundInterest(month));
    monthly2.append(String.valueOf(month+(". ")+monthlyAmount+"\n"));
    total2.setText(String.valueOf(d2));
}