Question

当我尝试运行此程序时，它为我的getTotalCost()函数输出0，我无法找出原因。

这是两个类文件：

ShoppingCart.cpp

#include "ShoppingCart.h"

#include <iostream>
#include <string>
using namespace std;

ShoppingCart::ShoppingCart()
{
    customerName = "None";
}

ShoppingCart::ShoppingCart(string name)
{
     customerName = name;
}

string ShoppingCart::getCustomerName() const
{
    return customerName;
}

void ShoppingCart::addItem(ItemToPurchase item)
{
    cartItems.push_back(item);
}

void ShoppingCart::removeItem(string name)
{
    for (int i = 0; i < cartItems.size(); i++)
    {
        if (cartItems.at(i).getName() == name)
        {
            cartItems.erase(cartItems.begin() + i);
        }
        else
        {
            cout << "Item not found in cart. Nothing removed." << endl;
        }
    }

}

void ShoppingCart::changeQuantity(string name, int quantity)
{
    for (int i = 0;  i < cartItems.size(); i++)
    {
        if (cartItems.at(i).getName() == name)
        {
            cartItems[i].setQuantity(quantity);
        }
        else
        {
            cout << "Item not found in cart. Nothing modified." << endl;
        }
    }
}

double ShoppingCart::getTotalCost()
{
    double sum = 0.0;
    for (int i = 0; i < cartItems.size(); i++)
    {
        sum += cartItems[i].getQuantity() * cartItems[i].getPrice();   
    }
    return sum;
}

void ShoppingCart::printCart()
{
    cout << customerName << "'s Shopping Cart" << endl;
    for (int i = 0; i < cartItems.size(); i++)
    {
        cartItems.at(i).printItemCost();
    }
    cout << endl;
    cout << "Total: $" << getTotalCost() << endl;
}

ShoppingCart.h

#ifndef ShoppingCart_hpp
#define ShoppingCart_hpp


#include <string>
#include <vector>
#include "ItemToPurchase.h"
using namespace std;

class ShoppingCart
{
    private:
       string customerName;
       vector<ItemToPurchase> cartItems;

    public:
       ShoppingCart();
       ShoppingCart(string name);
       string getCustomerName() const;
       void addItem(ItemToPurchase);
       void removeItem(string);
       void changeQuantity(string, int);
       double getTotalCost();
       void printCart();
};

#endif

Answer 1

我的怀疑是，getTotalCost添加了0个值：

cartItems[i].getQuantity() * cartItems[i].getPrice();

如果两个因子中的一个为零，则总和保持为0。

我被困在一个C ++程序上，我正在为我的计算机科学课写作

1 个答案: