java - 尝试将多个 double 添加到 java 中的数组

Question

我正在尝试将购买列表添加到数组，然后能够根据数组中的 double 执行一些计算。我在尝试将购买添加到双阵列时遇到问题这是我拥有的:

public abstract class Customer {

   protected String category;
   protected String acctNumber;
   protected String name;
   protected double[] purchases;
   protected static final double SALES_TAX_RATE = 0.08;

/**
*Reads in customer data.
*@param acctNumberIn customers account number.
*@param nameIn customers name.
*/   
   public Customer(String acctNumberIn, String nameIn) {

      acctNumber = acctNumberIn;
      name = nameIn;
      purchases = new double[0];

   }

在我遇到问题的地方添加购买方法:

public void addPurchases(double ... pur) {


      purchases = Arrays.copyOf(purchases, purchases.length + 1);
      int a = purchases.length;
      for (int i = 0; i < purchases.length; i++) {
         purchases[a] = pur;
         }


   }

Answer 1

问题是 pur 的类型是 double[]。因此，您需要创建一个新数组，其大小为 purchases + pur，并将 pur 的每个元素复制到 purchases 的末尾。

请尝试以下代码:

public void addPurchases(double ... pur) {
  int purchasesLength = purchases.length;
  int combinedLength = pur.length + purchasesLength;
  purchases = Arrays.copyOf(purchases, combinedLength);
  for (int i = purchasesLength, j = 0; i < combinedLength; i++, j++) {
     purchases[i] = pur[j];
  }
}