c++类型无法解析错误

我尝试在main函数中实例化一个类，像这样:

#include <iostream>
#include<vector>
#include "./repository/BookmarkRepository.h"
#include "./domain/bookmark.h"
#include <list>
#include <iterator>
using namespace std;
using namespace domain;
using namespace repository;
int main() {
cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
//here comes the error 
BookmarkRepository<Bookmark>* repo = new BookmarkRepository("./resources/bookmarks"); 
return 0;
 }

这是BookmarkRepository:

#ifndef BOOKMARKREPOSITORY_H_
#define BOOKMARKREPOSITORY_H_
#include <string>
#include <iostream>
#include <iterator>
#include <list>
#include <algorithm>
#include <fstream>
#include "../domain/bookmark.h"
using namespace domain;
using namespace std;
namespace repository{
template<class Entity>
 class BookmarkRepository {
std::string filename;
std::list<Entity>* entities;
public:
BookmarkRepository(std::string filename) :
    filename(filename) {
    loadEntities();
}
void save(domain::Bookmark b){
    this->entities.push_back(b);
    ofstream fout(filename.c_str(), ios::app);
    fout <<b<<"n";
    fout.close();
    }

void update(int id,domain::Bookmark b);
void refresh();
void remove(int id);

private:
void loadEntities(){
    string line;
    ifstream fin(filename.c_str());
    if (!fin.is_open()) {
        throw "could not open file";
    }
    while (fin.good()) {
        Bookmark b;
        fin >> b;
    }
    fin.close();
}
};
}

#endif /* BOOKMARKREPOSITORY_H_ */

这里是书签。h

#ifndef BOOKMARK_H_
#define BOOKMARK_H_
#include <string>

namespace domain {
class Bookmark {
int id;
std::string title;
std::string address;
public:
Bookmark(int id=0, const std::string& title="", const std::string& address="") :
        id(id),title(title),address(address){
}

const int getId() const;
const std::string& getTitle() const;
void setId(int id);
const std::string& getAddress() const;
void setTitle(const std::string& type);
void setAddress(const std::string& address);
friend std::ostream& operator<<(std::ostream&, const Bookmark&);
friend std::istream& operator>>(std::istream&, Bookmark&);
};
}

#endif /* BOOKMARK_H_ */

和书签。cpp

#include "bookmark.h"
#include <sstream>
namespace domain {
const int Bookmark::getId() const {
return id;
}
void Bookmark::setId(int id) {
this->id = id;
}
void Bookmark::setTitle(const std::string& title) {
this->title = title;
}
const std::string& Bookmark::getTitle() const {
return title;
}
void Bookmark::setAddress(const std::string& address) {
this->address = address;
}
const std::string& Bookmark::getAddress() const {
return address;
}

std::ostream& operator <<(std::ostream& os, const Bookmark& b) {
os << b.getId() << "," << b.getTitle() << ","
        << b.getAddress();
return os;
}
std::istream& operator >>(std::istream& is, Bookmark& b) {
using namespace std;
string line, token, title,address;
int id;
is >> line;
istringstream ss(line);
getline(ss, token, ',');
stringstream(token)>>id;
getline(ss, token, ',');
title = token;

getline(ss, token, ',');
address = token;
b.setId(id);
b.setTitle(title);
b.setAddress(address);
return is;
}
}

我收到的错误实际上更复杂:

此行有多个标记-"BookmarkRepository"前应该有"，"或";"-未使用的变量' repo ' [- unused-variable]无法将' int* '转换为' repository::BookmarkRepository* '初始化-"BookmarkRepository"之前的预期类型说明符-类型"BookmarkRepository"无法解析。

我讨厌c++，但是这周我有一场考试，所以如果能给我一些建议，告诉我不要做什么，以避免这类错误，我将非常感激。