java - 如何使用方法从 Map 返回值？

Question

在这种情况下如何返回 int 值？

import java.util.*;

    public class ShoppingCart {

    private Map<String, Purchase> shoppingCart = new HashMap<String, Purchase>();

    public void add (String product, int price) {
        Purchase purchase = new Purchase(product, 1, price);
        shoppingCart.put(product, purchase);
    }

    public int totalPrice() {
        //How do I accomplish this? I want to return all the prices summed together

        }
    }  
}

购买方法的构造函数是:

 public Purchase(String product, int amount, int price) {

Answer 1

您需要迭代 map 值和总价

例如，此代码将起作用。

 public int totalPrice() {
      int sum = 0;
       for(Purchase p:shoppingCart.values()){
            sum+=p.getPrice();
       }
       return sum;
  }