Java:返回用户输入

Question

在接收“公正税”时遇到问题。程序编译后，不会计算输出的销售税 - 只是返回“0”。然而，“销售”方法(不在列出的代码内)将确认并打印销售金额。不确定我做错了什么。谢谢!

  //...
  Purchase saleAmount = new Purchase();

  //...

  System.out.println("Please enter a positive (+) number for the sale amount: $");
  double saleAmt = input.nextDouble();
  saleAmount.setSale(saleAmt);

  //...

  System.out.println("The 5% tax applied is: " + saleAmount.getJustTax());

public class Purchase
 //all data types have been declared
 final double SALES_TAX = 0.05;
{
  //Initial Sale Cost
  public double getSale()
{
  return sale;
}

  public void setSale(double amount)
{
  amount = sale;
}

//Get Just Sales Tax
  public double getJustTax()
{
  return justTax;
}
  public void setJustTax(double sale)
{
  justTax = (sale * SALES_TAX);
}

}

Answer 1

setSale 方法中的分配是向后的。目前，它将 sale 中的任何内容分配给您的本地变量 amount。

改变

public void setSale(double amount)
{
  amount = sale;
}

至

public void setSale(double amount)
{
  sale = amount;
}