C++ 错误 c2679 : binary '[' : no operator found which takes a right-hand operand of type 'SalesItem' (or there is no acceptable conversion)

Question

我是这个站点的新手(如果我做错了，我深表歉意)，而且是 c++ 的新手。我在为我的 C++ 类赋值时遇到了一个烦人的错误

c++ 错误 c2679:二进制“[”:未找到采用“SalesItem”类型右手操作数的运算符(或没有可接受的转换)

我不太确定我需要包含哪些内容才能帮助获得答案。我已经包含了我认为最相关的类，省去了带有 main() 的类。我没有包含标题，但如果需要我应该能够添加这些标题......

这是我发现此错误的 Invoice 类，我用 astriks(*) 标记了发生错误的行:

#include "stdafx.h"
#include <iostream>
#include "Invoice.h"
#include <vector>
#include <string>
using namespace std;

static int nextInvoiceNum = 1000;
Invoice::Invoice(const string name, const int vectorSize)
{
    customerName = name;
    salesItems.reserve(vectorSize);
    invoiceNumber = nextInvoiceNum++;
}

void Invoice::setCustomerName(string name)
{
    customerName = name;
}
string Invoice::getCustomerName()
{
    return customerName;
}
int Invoice::getInvoiceNumber()
{
    return invoiceNumber;
}
void Invoice::display()
{
    cout << "-------------------------\n";
    cout << "\n Invoice #: " << getInvoiceNumber() << "\n";
    cout << "\n Customer name: " << getCustomerName() << "\n";
    cout << "-------------------------\n";
    cout << "Items Purchased";
    cout << "-------------------------\n";
    for (auto &item : salesItems)
    {
********cout << salesItems[item].display() << "\n";
        cout << "-------------------------\n";
    }
}

void Invoice::addSalesItem(SalesItem&)
{
    salesItems.push_back(SalesItem());
}

double Invoice::getInvoiceAmount()
{
    double runningTot = 0;
    double total = 0;
    for (auto &item : salesItems)
    {
********runningTot = salesItems[item].getPartQuantity() * salesItems[item].getPartPrice();
        total += runningTot;
    }
    return total;
}

Invoice::~Invoice(void)
{
}

我试图做的是使用一个对象 vector ，当我尝试使用该 vector 从 SalesItems 类调用 display() 方法时，首先出现错误的地方。

这是 SalesItem 类:

#include "stdafx.h"
#include "SalesItem.h"
#include <iostream>
using namespace std;


SalesItem::SalesItem(string partNumber, string partDescription, int partQuantity, double partPrice)
{
    partNumber = "";
    partDescription = "";
    partQuantity = 0;
    partPrice = 0;
}


SalesItem::~SalesItem(void)
{
}

void SalesItem::setPartNumber(string number)
{
    partNumber = number;
}
void SalesItem::setPartDescription(string description)
{
    partDescription = description;
}
void SalesItem::setPartQuantity(int quantity)
{
    partQuantity = quantity;
}
void SalesItem::setPartPrice(double price)
{
    partPrice = price;
}

string SalesItem::getPartNumber()
{
    return partNumber;
}
string SalesItem::getPartDescription()
{
    return partDescription;
}
int SalesItem::getPartQuantity()
{
    return partQuantity;
}
double SalesItem::getPartPrice()
{
    return partPrice;
}

void SalesItem::display()
{
    cout<< "-------------------------:";
    cout<< "\n Part number: " << getPartNumber() << "\n";
    cout<< "\n Part description: " << getPartDescription() << "\n";
    cout<< "\n Part quantity: " << getPartQuantity() << "\n";
    cout<< "\n Part price: $" << getPartPrice() << "\n";
    cout<< "\n Invoice amount: $" << getInvoiceAmount() << "\n";
}

double SalesItem::operator+(double total)
{
    double subtotal = getPartQuantity() * getPartPrice();
    total += subtotal;
    return total;
}

double SalesItem::getInvoiceAmount()
{
    double invoice = getPartQuantity() * getPartPrice();
    return invoice;
}

再次抱歉，如果我以错误的方式发布此内容。我真的很感激这方面的帮助。将提供任何其他必要信息或及时进行更改。

谢谢!

Answer 1

它说方括号内的东西是一个 salesItem 对象，但它需要一个整数。方括号的正常使用是从集合中挑选出一个项目，使用某种索引，通常是一个整数。不过，在这种情况下，您的 for 循环已经 挑选出了该项目，因此您可以只说“item.display()”而不是“salesItem[item].display()”。

(如果您的代码看起来有点像这样，您将使用 salesItem[item].display():)

int item;
for (item=0; item < ?however many sales items you have? ; item++) {
    bla bla salesItem[item].display()
}