Visual Studio不会看到成员函数

Question

我有一个名为person的班级。在person.h我有这个：

#include "stdafx.h"
#include "Resource.h"
#pragma once

class person
{
private:
   std::string firstName;
   std::string lastName;
   int age;
   Resource *resource;

public:
   person(std::string first,
          std::string last,
          int age);
   ~person();
   person(person& p);

   bool operator < (const person& currentPerson) const;
   bool operator < (int number) const;

   void        setFirst(std::string first) {firstName = first;}
   void        setLast(std::string last) {lastName = last;}
   std::string getName() const;
   std::string getFirst() const;
   std::string getLast() const;
   int         getAge() const {return age;}
   void        setAge(int newAge) {age = newAge;}
   void        addResource();

   friend bool operator < (int number, const person& currentPerson);
};

bool operator < (int number, const person& currentPerson);

除了我刚刚添加到课程中的setFirst和setLast之外，每个函数都能正常工作。我打电话的时候，

#include "stdafx.h"
#include "Resource.h"
#include "person.h"

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
   person Kenneth("Kenneth", "Cochran", 19);
   Kenneth.addResource();
   Kenneth.setFirst("Kenny");
   Kenneth.setLast("Cochran");
   Kenneth.addResource();
   return 0;
}

Visual Studio说

freestore.cpp(14): error C2039: 'setFirst' : is not a member of 'person'
person.h(5) : see declaration of 'person'
freestore.cpp(15): error C2039: 'setLast' : is not a member of 'person'
person.h(5) : see declaration of 'person'