Question

我试图创建一个非常简单的VCard，但我得到一个非const左值引用类型无法绑定我的main.cpp中的错误，并且无法解决这个问题。问题是......

vc-＆gt; createVCard（“JasonSteindorf.vcf”，＆amp; p1）;

// Person.h

#ifndef JASONSTEINDORF_PERSON_H
#define JASONSTEINDORF_PERSON_H

#include <string>
using std::string;

namespace JasonSteindorf{

    class Person{
    public:
        Person();
        Person(string firstName,string lastName,string phoneNumber,string email)
            : firstName(firstName), lastName(lastName), phoneNumber(phoneNumber), email(email){}

        inline string getFirstName(){ return firstName; }
        inline string getLastName(){ return lastName; }
        inline string getPhoneNumber(){ return phoneNumber; }
        inline string getEmail(){ return email; }

    private:
        string firstName, lastName, phoneNumber, email;
    };
}

#endif

// VCard.h

#ifndef JASONSTEINDORF_VCARD_H
#define JASONSTEINDORF_VCARD_H


#include "Person.h"

#include <string>
using std::string;

namespace JasonSteindorf{

    class VCard{

    public:
        void createVCard(string fileName, Person &p);
        string getVCard(Person &p);
    };
}

#endif

// VCard.cpp

#include "VCard.h"

#include <fstream>
using std::ofstream;

#include <string>
using std::string;

#include <sstream>
#include <iostream>
using std::ostringstream;


using namespace JasonSteindorf;

//Writes the VCard to a file
string getVCard(Person &p){
    ostringstream os;

    os << "BEGIN:VCARD\n"
       << "VERSION:3.0\n"
       << "N:" << p.getLastName() << ";" << p.getFirstName() << "\n"
       << "FN:" << p.getFirstName() <<" " << p.getLastName() << "\n"
       << "TEL:TYPE=CELL:" << p.getPhoneNumber() << "\n"
       << "EMAIL:" << p.getEmail() << "\n"
       << "URL:" << "http://sorcerer.ucsd.edu/html/people/jason.html" << "\n"
       << "REV:20110719T195243Z" << "\n"
       << "END:VCARD\n";

    return os.str();
}

//Returns a string containing the VCard format
void createVCard(string fileName, Person &p){
    string vCard = getVCard(p);

    ofstream outputFile("/Users/jsteindorf/Desktop/" + fileName);
    outputFile << vCard;
}

// main.cpp中

#include "Person.h"
#include "VCard.h"

#include <iostream>

using namespace JasonSteindorf;

int main(int argc, const char * argv[])
{

    VCard *vc = new VCard();
    Person *p1 = new Person ("Jason", "S", "858-555-5555", "js@ucsd.edu");

    vc->createVCard("JS.vcf", &p1);

    return 0;
}

Answer 1

您尚未将函数createVCard和getCard定义为VCard类的成员函数。

这些是全球功能。使用范围解析运算符::将它们定义为类的成员函数，如

  void Vcard::createVCard(string fileName,Person &p)
  {
    ....
    ....
  }
  string Vcard::getVCard(Person &p)
  {
    ....
    ....
  }

此外，您的createVCard函数接受对Person的引用，因此您必须将对象传递给不是指向对象(&p)的指针的地址的人，也不会传递对象的地址(p)代替*p取消引用该对象，因此调用看起来像vc->createVCard("JS.vcf", *p1)

非const左值对类型的引用不能绑定错误

1 个答案: