出现了一些莫名其妙的连接错误

[jhxtty]

在学设计模式，这是个观察者模式
头文件：

#ifndef Observer_hpp
#define Observer_hpp

#include <stdio.h>
#include <vector>
#include <string>
#include <iostream>
class Observer;
class Subject{
public:
    virtual void attach(Observer* o);
    virtual void detach(Observer* o);
    virtual void notify();
    virtual std::string getStatus();
    virtual void setStatus(const std::string &s);
    virtual ~Subject()=0;
};

class Observer{
public:
    virtual void setSubject(Subject *s);
    virtual void update();
    virtual ~Observer()=0;


};

class ConcreteSubject: public Subject{
    std::vector<Observer*> v;
    std::string status;
public:
    void attach(Observer *o);
    void detach(Observer *o);
    void notify();
    void setStatus(const std::string &s);
    std::string getStatus();
};

class ConcreteObserver:public Observer{
    std::string name_;
    Subject *subject_;
public:
    ConcreteObserver(const std::string &s):name_(s){}
    void update();
    void setSubject(Subject *s);
};
#endif /* Observer_hpp */

cpp文件：

#include "Observer.hpp"
Subject::~Subject(){}
Observer::~Observer(){}

//void ConcreteSubject::attach(Observer *o){
//    o->setSubject(this);
//    v.push_back(o);
//}
void ConcreteSubject::detach(Observer *o){
    auto i=v.begin();
    for(;*i!=o&&i!=v.end();i++);
    if(i!=v.end()){
        v.erase(i);
    }
}

void ConcreteSubject::setStatus(const std::string &s){
    status=s;
    notify();
}
std::string ConcreteSubject::getStatus(){
    return status;
}
void ConcreteSubject::notify(){
    for(auto &i:v){
        i->update();
    }
}

void ConcreteObserver::setSubject(Subject *s){
    subject_=s;
}



//
//void ConcreteObserver::update(){
//    std::cout<<name_<<"收到消息："<<subject_->getStatus()<<std::endl;
//
//}

被注释的两个函数无法实现，取消注释就会连接错误