c如何正确地将.cpp拆分为.cpp和.h

我之前使用过.h文件,但从未真正将.cpp分成.cpp和.h.

我知道.h文件仅用于声明而.cpp用于定义,我试图将.cpp拆分为.cpp和.h但我收到很多错误,所以我想知道是否有人可以帮助我我的代码.

以下类是尚未拆分为.cpp和.h的类,只是为了向您展示“之前的版本”.

TicketOrder.cpp

#include <iostream>

using namespace std;

class TicketOrder
{

private :

        char type;
        int quantity;

public :

          friend std::ostream& operator<<(std::ostream& os,TicketOrder const& order)
         {
                 os << " Type: " << order.type << ",Quantity: " << order.quantity;
                 return os;
         }


        //Getters

        int getQuantity() const;
         {
                        return quantity;
         }

        char getType() const;
          {
                        return type;
          }

        //Setters    

        void setQuantity (int x)
                {
                        quantity =x;
                }

        void setType(char y)
                {
                        type =y;
                }   
};

现在,我将上面的类拆分为.cpp和.h

TicketOrder.cpp

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

class TicketOrder
{

        //Getters

        int getQuantity() const
                {
                        return quantity;
                }

        char getType() const
                {
                        return type;
                }

        //Setters

        void setQuantity (int x)
                {
                        quantity =x;
                }

        void setType(char y)
                {
                        type =y;
                }        
};

TicketOrder.h

#include <iostream>

using namespace std;

class TicketOrder
{

private :

        char type;
        int quantity;

public :

          friend std::ostream& operator<<(std::ostream& os,TicketOrder const& order)
        {
                 os << " Type: " << order.type << ",Quantity: " << order.quantity;
                 return os;
        }

        //Getters

        int getQuantity() const;    
        char getType() const;

        //Setters

        void setQuantity (int x);    
        void setType(char y);       
};

我还有一个用于包含我不会在这里包含的主类的类,因为它很长并且我认为它不重要因为我知道我正在做.h和.cpp错误.

当我尝试编译main时,它给了我这个错误：

Undefined                       first referenced
 symbol                             in file
TicketOrder::getQuantity() const    /var/tmp//ccaSflFG.o
TicketOrder::setType(char)          /var/tmp//ccaSflFG.o
TicketOrder::setQuantity(int)       /var/tmp//ccaSflFG.o
ld: fatal: Symbol referencing errors. No output written to a.out
collect2: ld returned 1 exit status

任何人都可以帮我拆分.h和.cpp吗？或者给我一些建议？我做了很多研究,无法弄清楚出了什么问题.

谢谢.