C++ 运算符 >> 重载

Question

我有一个如下的客户类，

#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include "SimpleDate.h"

using namespace std;

class Customer {

private:
    string customerId;
    string name;
    string address;
    string city;
    string postCode;
    SimpleDate* dateLastPurchased;
    double dollarsOwed;

public:
    //Customer(string customerIdVal, string nameVal);
    Customer();
    string getCustomerId();
    string getName();
    void setAddress(string addressVal);
    string getAddress();
    void setPostCode(string postCodeVal);
    string getPostCode();
    void setCity(string cityVal);
    string getCity();
    void setDateLastPurchased(SimpleDate* date);
    SimpleDate* getDateLastPurchased();
    void addDollarsOwed(double amount);
    double getDollarsOwed();

    friend ostream& operator<< (ostream &out, Customer &cust);
    friend istream& operator>> (istream &in, Customer &cust);
};

cpp 文件中的重载部分如下所示

ostream& operator<< (ostream &out, Customer &cust)
{
    out << cust.customerId << "\t" << cust.name << "\t" << cust.address << "\t" << cust.city << "\t" << cust.postCode << "\t" << cust.dateLastPurchased->getFullDate() << "\t" << cust.dollarsOwed << "\t" << std::endl;
    return out;
}

istream& operator>> (istream &in, Customer &cust)
{
    in >> cust.customerId;
    in >> cust.name;
    in >> cust.address;
    in >> cust.city;
    in >> cust.postCode;

    string stringData;
    in >> stringData;

    std::istringstream iss(stringData);
    std::string datePart;
    int tmp;
    vector<int> dateData;

    while(std::getline(iss, datePart, '/')) {

        sscanf(datePart.c_str(), "%d", &tmp);       
        dateData.push_back(tmp);
    }

    SimpleDate* date = new SimpleDate(dateData[2], dateData[1], dateData[0]);
    cust.dateLastPurchased = date;

    string stringDollarsOwed;
    in >> stringDollarsOwed;

    sscanf(stringDollarsOwed.c_str(), "%lf", &cust.dollarsOwed);

    return in;
}

然后在我的主类中，我尝试创建一个客户对象，如下所示，

Customer* cust = new Customer();

    cust << customerInfo[0] << customerInfo[1] << customerInfo[2] << customerInfo[3] << customerInfo[4] << customerInfo[5] << customerInfo[6];

但是当我编译时出现以下错误，

你能帮忙吗？

谢谢。

AppManager.cpp: In member function 'Customer* AppManager::createCustomerObject(std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >)':
AppManager.cpp:445: error: no match for 'operator<<' in '& cust << customerInfo.std::vector<_Tp, _Alloc>::operator[] [with _Tp = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Alloc = std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >](0u)'
Customer.h:46: note: candidates are: std::ostream& operator<<(std::ostream&, Customer&)
*** Error code 1
make: Fatal error: Command failed for target `Tour'

Answer 1

这个运营商:

ostream& operator<< (ostream &out, Customer &cust)

允许你做类似的事情

Customer c;
std::cout << c << std::endl;
std::ofstream output("customers.txt");
output << c << std::endl;

并且不是

Customer c;
c << x;

绝对不是

Customer* c = ...;
c << x;