java - 无法找出java中伪代码转换的数据

Question

int month = 1;                                              
int balance = 500;                                              
int totalpaid = 0;                                              
double interest;                                                
  while (balance > 100);                                                
{                                               
  balance = balance - 100;                                              
  interest = (balance * 0.1);                                               
  balance = totalpaid + interest;                                               
  totalpaid = totalpaid + 100;                                              
  month = month + 1;                                                
}                                               
System.out.println ("you paid" + "," + totalpaid);                                              
System.out.println ("it took you" + "," + month + "months"); 

我本质上是想找出这段代码中的错误，错误是当我尝试将总付款和利息加在一起时出现的。

Answer 1

balance 是一个 int，您正在尝试将 totalpaid (int) 和 interest (double) 添加在一起。你不能这样做，你必须对相同的数据类型进行操作。 理论上，您可以将结果转换为 int，错误就会消失:

  balance = (int) totalpaid + interest;                                               

但不要这样做。使用 int 和 double 处理货币并不是正确的方法，因为它不准确，并且可能会导致浮点错误。请改用 BigDecimal。

 public static void main(String[] args) {
        int month = 1;
        BigDecimal balance = BigDecimal.valueOf(500);
        BigDecimal totalpaid = BigDecimal.valueOf(0);
        BigDecimal interest;
        while (balance.compareTo(BigDecimal.valueOf(100)) > 0)
        {
            balance = balance.subtract(BigDecimal.valueOf(100));
            interest = (balance.multiply(BigDecimal.valueOf(0.1)));
            balance =  (totalpaid.add(interest));
            totalpaid = totalpaid.add(BigDecimal.valueOf(100));
            month = month + 1;
        }
        System.out.println ("you paid" + "," + totalpaid.toString());
        System.out.println ("it took you" + "," + month + "months");
    }