请各位帮我把这个代码里的读文件和写文件删掉，删掉就好

#include<iostream>
#include<sstream>
#include<fstream>
#include<numeric>
#include<algorithm>
#include<string>
#include<unordered_map>
#include<unordered_set>

using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;

const string file = "D:\\mytest.txt";

unordered_map<string , int> sheng , shi;

class person
{
public:
    person() = default;
    person(string a , string b , string c , string d , string e) : name(a) , age(b) , sheng(c) , shi(d) , id(e) {}
    string name;                        //名字
    string age;                         //性别
    string sheng;                       //省份
    string shi;                         //市区
    string id;                          //身份证号码
    person* next;
    person* prew;
};

void insert_person(person* x , person*& root)
{
    sheng[x -> sheng]++;
    shi[x -> shi]++;
    x -> next = root;
    if(root)
        root -> prew = x;
    root = x;
    x -> prew = nullptr;
}


void read_file(person*& root)
{
    ifstream fi(file);
    while(fi)
    {
        string line;
        getline(fi , line);
        stringstream ss(line);
        string a , b , c , d , e;
        ss >> a >> b >> c >> d >> e;
        person* per = new person(a , b , c , d, e);
        sheng[per -> sheng]++;
        shi[per -> shi] ++;
        insert_person(per, root);
    }
    fi.close();
}


void delete_person(person* x , person*& root)
{
    sheng[x -> sheng]--;
    shi[x -> shi]--;
    if(x -> prew)
        x -> prew -> next = x -> next;
    else
        root = x -> next;
    if(x -> next)
        x -> next -> prew = x -> prew;
}

person* search_person(string id , person* root)
{
    while(root)
    {
        if(root -> id == id)
            break;
        root = root -> next;
    }
    return root;
}

void write_file(person* root)
{
    ofstream of(file);
    while(root)
    {
        of << root -> name <<  " " << root -> age << " "  << root -> sheng << " " << root -> shi << " " << root -> id;
        root = root -> next;
        if(root)
            of << "\n";
    }
    of.close();
}

void xiugai(person* p)
{
    string a ,b , c , d , e;
    cout << "请重新输入该改身份证信息：\t";
    --sheng[p -> sheng];
    --shi[p -> shi];
    cin >> a >> b >> c >> d >> e;
    p -> name = a;
    p -> age = b;
    p -> sheng = c;
    p -> shi = d;
    p -> id = e;
    ++sheng[p -> sheng];
    ++shi[p -> shi];
}

void view(person*& root)
{
    string s;
    
    while(true)
    {
        cout<<"\n\t\t\t 欢 迎 使 用 身 份 管 理 系 统 !"<<endl;
        cout << "1---------------------给定身份证号码显示其身份信息" << endl;
        cout << "2---------------------给定一个省份，显示该省份的人员的数量"  << endl;
        cout << "3---------------------给定一个地区，显示该地区的人员的数量" << endl;
        cout << "4---------------------添加一个身份信息" << endl;
        cout << "5---------------------给定一个身份证号码，修改该身份信息" << endl;
        cout << "6---------------------给定一个身份证号码，删除该身份信息" << endl;
        cout << "0---------------------退出系统" << endl;
        cout << "请输入一个想要使用的功能：\t";
        cin >> s;
        if(s == "0")
            break;
        if(s == "1")
        {
            string id;
            cout << "请输入一个身份证id :\t";
            cin >> id;
            cout << endl;
            auto q = search_person(id, root);
            if(q)
            {
                cout << "所要查找的信息如下：" << endl;
                cout << q -> name << " "  << q -> age << " " << q -> sheng << " " << q -> shi << " "  << q -> id << endl;
            }
            else
                cout << "所要查找的身份证信息不存在！" << endl;
        }
        else if(s == "2")
        {
            string now;
            cout << "请输入一个想要查找的省份：\t";
            cin >> now;
            cout << endl;
            cout << "该省份的人数为：\t";
            cout << sheng[now];
            cout << endl;
        }
        else if(s == "3")
        {
            string now;
            cout << "请输入一个想要查找的市区：\t";
            cin >> now;
            cout << endl;
            cout << "该市区的人数为：\t";
            cout << shi[now];
            cout << endl;
        }
        else if(s == "4")
        {
            cout << "请分别输入想要添加的人员的相关信息:\t";
            string a , b ,c  , d , e;
            cin >> a >> b >> c >> d >> e;
            cout << endl;
            person* p = new person(a , b , c ,d , e);
            insert_person(p, root);
        }
        else if(s == "5")
        {
            cout << "请输入一个想要修改的身份证号码:\t";
            string now;
            cin >> now;
            cout << endl;
            auto q = search_person(now, root);
            if(q)
            {
                xiugai(q);
            }
            else
                cout << "所输入的身份证id不存在！" << endl;
        }
        else if(s == "6")
        {
            cout << "请输入一个想要删除的身份证号码:\t";
            string now;
            cin >> now;
            cout << endl;
            auto q = search_person(now, root);
            if(q)
            {
                delete_person(q , root);
            }
            else
                cout << "所想要删除的身份证id不存在！" << endl;
        }
    }
}

int main()
{
    person* root;
    read_file(root);
    view(root);
    write_file(root);
    return 0;
}