C ++ Ostream运算符问题

Question

嗨，我有这个ostream运算符，在编译时会出现此错误： cannot access private member declared in class 'CService'

这是我的代码：

friend ostream& operator <<(ostream& os, CService &obj);

ostream& operator<<(ostream &os, CService &obj) {

os<<obj.m_strClient;
return os;

}

我尝试返回ostream&但这不能解决问题，相反，它添加了另一个错误syntax error : ';'

这是我的整个代码：

#include <iostream>
#include <string>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

class CService {
private:
    string m_strClient;
    string m_strSeller;
    int m_iMinutes;

public:
    CService() {

        m_strClient="N/A";
        m_strSeller="N/A";
        m_iMinutes=0;
    }

    CService( string c, string s, int m ) {

        m_strClient=c;
        m_strSeller=s;
        m_iMinutes=m;

    }

    CService(const CService &obj ) {

        m_strClient=obj.m_strClient;
        m_strSeller=obj.m_strSeller;
        m_iMinutes=obj.m_iMinutes;

    }

    string GetClient() {

        return m_strClient;

    }

    string GetSeller() {

        return m_strSeller;

    }

    int GetMusic() {

        return m_iMinutes;

    }

    CService CService::operator =(CService obj) {

        m_strClient=obj.m_strClient;
        m_strSeller=obj.m_strSeller;
        m_iMinutes=obj.m_iMinutes;
        return *this;

    }

    bool operator < (const CService &obj) const {

        return m_strSeller<obj.m_strSeller;

    }

    CService CService::operator +(const CService &obj) const {

        return CService( m_iMinutes+obj.m_iMinutes );

    }

    friend ostream& operator <<(ostream& os, CService &obj);



    bool CService::operator==(CService &obj) {

        return (obj.m_strSeller==m_strSeller);

    }
};

ostream& operator<<(ostream &os, CService &obj) {

    os<<obj.m_strClient;
    return ostream&;

}

Answer 1

您有很多问题，主要问题是：

• return os; 而不是return ostream&;

• 您没有接受int构造函数：add CService(int m = 0)

• 您不应该在类定义中添加CService::和：删除它们

我更正了它们（ 实时代码 ），至少它将被编译而没有错误：

class CService
{
private:
    string m_strClient;
    string m_strSeller;
    int m_iMinutes;

public:

    CService(int m = 0)
    {
        m_strClient = "N/A";
        m_strSeller = "N/A";
        m_iMinutes = m;
    }

    CService(string c, string s, int m)
    {
        m_strClient = c;
        m_strSeller = s;
        m_iMinutes = m;
    }

    CService(const CService &obj)
    {
        m_strClient = obj.m_strClient;
        m_strSeller = obj.m_strSeller;
        m_iMinutes = obj.m_iMinutes;
    }

    string GetClient()
    {
        return m_strClient;
    }

    string GetSeller()
    {
        return m_strSeller;
    }

    int GetMusic()
    {
        return m_iMinutes;
    }

    CService operator =(CService obj)
    {
        m_strClient = obj.m_strClient;
        m_strSeller = obj.m_strSeller;
        m_iMinutes = obj.m_iMinutes;
        return *this;
    }

    bool operator<(const CService &obj) const
    {
        return m_strSeller < obj.m_strSeller;
    }

    CService operator +(const CService &obj) const
    {
        return CService(m_iMinutes + obj.m_iMinutes);
    }

    friend ostream& operator <<(ostream& os, CService &obj);

    bool operator==(CService &obj)
    {
        return (obj.m_strSeller == m_strSeller);
    }
};

ostream& operator<<(ostream &os, CService &obj)
{
    os << obj.m_strClient;
    return os;
}