（关于vector容器<<重载）有点苦逼了，一个简单的代码搞了一下午，报了一屏错误，求高手解救没在线等
#include <iostream>
#include <vector>
#include <string.h>
#include <functional>
#include <algorithm>
#include <stdio.h>

using namespace std;

class address_list
{
public:
address_list(){}
address_list(string _name,int _number):name(_name),number(_number){}
friend ofstream & operator << (ofstream &out ,address_list st)//这行报错
{
out << "姓名:"<<st.name<<"号码:"<<st.number<<endl;
return out;
}
private:
string name;
int number;
};
void show_info(vector<address_list> &vec)//这里报错
{
vector<address_list>::iterator it;
for(it = vec.begin(); it != vec.end(); it++)
{
cout<<*it<<" ";
}
cout<<endl;
}
int main()
{
vector<address_list> vec;
return 0;
} vector
[解决办法]
ofstream 改为 ostream
加上#include<string>