我写了个石头剪子布，增加写入功能，可以读取数据

//computer.cpp
#include "Computer.h"
void Computer::Input() {
    srand((unsigned)time(0));
    for (int i = 0; i < 10; i++) {
        radom = rand() % 3;
    }
    switch (radom) {
    case 0:setbase(0);
        break;
    case 1:setbase(1);
        break;
    case 2:setbase(2);
        break;
    }
}
void Computer::Show()const {
    cout << "电脑出的是：" << getbase() << endl;
}
void Computer::Read(fstream& f) const {
    f.read((char*)this, sizeof(Computer));
}
void Computer::Write(fstream& f)const {
    f.write((char*)this, sizeof(Computer));
}

//computer.h
#pragma once
#include"project.h"
class Computer:virtual public project
{
public:
    Computer() {};
    virtual ~Computer() {};
    void Input();
    void Show()const;
    void Read(fstream& f)const;
    void Write(fstream& f)const;
};

以上是COMPUTER类的声明和实现

//people.h
#pragma once
#include"project.h"
class people:virtual public project
{
public:
 people() {};
 virtual ~people() {};
 void Input();
 void Show()const;
 void Read(fstream& f)const;
 void Write(fstream& f)const;
};

//people.cpp 
1#include "people.h"
void people::Input() {
    cout << "请输入石头（1），剪刀（2），布（3）" << endl;
    cin >> num;
    switch (num) {
    case 1:setbase(0);
        break;
    case 2:setbase(1);
        break;
    case 3:setbase(2);
        break;
    default:
        cout << "输入失败！" << endl;
        Input();
    }
}
void people::Show() const {
    cout << "您出的是：" << getbase() << endl;
}
void people::Read(fstream&f) const {
    f.read((char*)this, sizeof(people));
}
void people::Write(fstream& f)const {
    f.write((char*)this, sizeof(people));
}

//PROJECT.H
#pragma once
#include<iostream>
#include<string>
#include<time.h>
#include<fstream>
using namespace std;
enum base { rock, scissor, cloth };
class project
{
protected:
    int num;
    int radom;
public:
    virtual ~project() {};
    virtual void Input() = 0;
    void setbase(int b) {
        num = (base)b;
    }
    int getnum() {
        return num;
    }
    string getbase() const {
        string c;
        if (num == 0) {
            c = "石头";
        }
        else if (num == 1) {
            c = "剪刀";
        }
        else
            c = "布";
        return c;
    }
    virtual void Show()const = 0;
    virtual void Read(fstream& f)const = 0;
    virtual void Write(fstream& f)const = 0;
};

//systemm.h
#pragma once
#include"people.h"
#include"Computer.h"
#include"usertype.h"
class systemm 
{
protected:
    fstream file;
    usertype* usertable;
    int maxSize;                                            
    int count;        
public:
    systemm();
    ~systemm();
    void Adduser(const usertype& e);
    void adddate();
    void run();
    void show();
};

//systemm.cpp
#include "systemm.h"
static double wins = 0.0;
bool inline UserSaysYes()
{
    char flag = 'N';
    cin >> flag;
    if (flag == 'y' || flag == 'Y')
    {
        return true;
    }
    else
    {
        return false;
    }
}
systemm::systemm()
{
    ifstream userfile("user.idx", ios::binary);                
    if (!userfile.fail())
    {
        userfile.seekg(0, ios::end);                            
        count = userfile.tellg() / sizeof(systemm);            
        maxSize = count + 100;
        usertable = new usertype[maxSize];                    
        userfile.seekg(0, ios::beg);                            
        int i = 0;                                                
        userfile.read((char*)& usertable[i++], sizeof(usertype));
        while (!userfile.eof())
        {        
            userfile.read((char*)& usertable[i++], sizeof(usertype));
        }
        userfile.close();                                        
    }
    else
    {        
        count = 0;                                                
        maxSize = count + 100;                        
        usertable = new usertype[maxSize];                    
    }
    ifstream iFile("user.dat");                                
    if (iFile.fail())
    {                                                            //打开文件失败，表示文件不存在
        ofstream oFile("user.dat");                            //建立输出文件
        if (oFile.fail())throw("打开文件失败!");                //抛出异常
        oFile.close();                                            //关闭文件
    }
    else
    {    
        iFile.close();                                            //关闭文件
    }
    file.open("user.dat", ios::in | ios::out | ios::binary);        //以读写的方式打开文件
    if (file.fail())throw("打开文件失败!");                        //抛出异常
}
systemm::~systemm()
{
    ofstream userfile("user.idx", ios::binary);            
    for (int i = 0; i < count; i++)
    {
        userfile.write((char*)& usertable[i], sizeof(usertype));
    }
    userfile.close();                                    
    file.close();                                            
}
void systemm::Adduser(const usertype& e)
{
    if (count >= maxSize)        //扩展缓存区长度，主要是为了防止缓存区溢出
    {
        maxSize += 100;
        usertype* temusertable = new usertype[maxSize];
        for (int i = 0; i < count; i++)
        {
            temusertable[i] = usertable[i];
        }
        delete[]usertable;
        usertable = temusertable;
    }
    //添加元素
    usertable[count++] = e; //加入到索引表中
}
void systemm::adddate()
{
    Computer* computer = new Computer;
    people* peo = new people;
    usertype computeritem;    
    computeritem.usertype = '1';
    usertype peopleitem;
    peopleitem.usertype = '2';
    int ss = 3;
    int f = 0;
    file.seekg(0, ios::end);        //将dat文件的指针指向末尾，为下一步的增加数据做准备
    do                            //第一个循环，来确认是否继续输入
    {
        do {
            if (f > 0) {
                Computer* computer = new Computer;
                people* peo = new people;
            }
            computer->Input();
            peo->Input();
            if (computer->getnum() == 0 && peo->getnum() == 1) {
                computer->Show();
                peo->Show();
                ss = 0;
            }
            else if (computer->getnum() == 1 && peo->getnum() == 2) {
                computer->Show();
                peo->Show();
                ss = 0;
            }
            else if (computer->getnum() == 2 && peo->getnum() == 0) {
                computer->Show();
                peo->Show();
                ss = 0;
            }
            else if (computer->getnum() == 0 && peo->getnum() == 2) {
                computer->Show();
                peo->Show();
                ss = 1;
            }
            else if (computer->getnum() == 1 && peo->getnum() == 0) {
                computer->Show();
                peo->Show();
                ss = 1;
            }
            else if (computer->getnum() == 2 && peo->getnum() == 1) {
                computer->Show();
                peo->Show();
                ss = 1;
            }
            else if (computer->getnum() == 0 && peo->getnum() == 0) {
                computer->Show();
                peo->Show();
                ss = 2;
            }
            else if (computer->getnum() == 1 && peo->getnum() == 1) {
                computer->Show();
                peo->Show();
                ss = 2;
            }
            else if (computer->getnum() == 2 && peo->getnum() == 2) {
                computer->Show();
                peo->Show();
                ss = 2;
            }
            if (ss == 2) {
                cout << "平局，请继续";
                computeritem.num = computer->getnum();
                peopleitem.num = peo->getnum();
                computeritem.position = file.tellg();
                Adduser(computeritem);
                computer->Write(file);
                delete computer;
                file.seekg(0, ios::end);             
                peopleitem.position = file.tellg();
                Adduser(peopleitem);
                peo->Write(file);
                delete peo;
            }
            f++;
        } while (ss == 2);
        if (ss == 1) {
            cout << "你输了" << endl;
            computeritem.num = computer->getnum();
            peopleitem.num = peo->getnum();
            computeritem.position = file.tellg();
            Adduser(computeritem);
            computer->Write(file);
            delete computer;
            file.seekg(0, ios::end);
            peopleitem.position = file.tellg();
            Adduser(peopleitem);
        }
        else {
            cout << "你赢了" << endl;
            wins += 1;
            computeritem.num = computer->getnum();
            peopleitem.num = peo->getnum();
            computeritem.position = file.tellg();
            Adduser(computeritem);
            computer->Write(file);
            delete computer;
            file.seekg(0, ios::end);
            peopleitem.position = file.tellg();
            Adduser(peopleitem);
        }
        peo->Write(file);
        cout << "是否要继续添加？";
        delete peo;
    } while (UserSaysYes());
}
void systemm::show() {
    Computer* computer = new Computer;
    people* peo = new people;
    int pos;
    file.seekg(0, ios::beg);
    for (pos = 0; pos < count; pos++) {
        if (usertable[pos].usertype == '1') {
            cout << "第" << pos + 1 << "局" << endl;
            file.seekg(usertable[pos].position, ios::beg);
            computer->Read(file);
            computer->Show();
        }
        else {
            cout << "第" << pos + 1 << "局" << endl;
            file.seekg(usertable[pos].position, ios::beg);
            peo->Read(file);
            peo->Show();
        }
    }
    cout << "胜率为：" << (wins / (pos + 1)) * 100 << "%" << endl;
    if (pos == 0) {
        cout << "数据为空" << endl;
    }
}
void systemm::run() {
    int select;
    do
    {
        cout << "请选择" << endl;
        cout << "1.开始/继续游戏" << endl;
        cout << "2.显示游戏记录" << endl;
        cout << "3.退出游戏" << endl;
        cin >> select;
        while (cin.get() != '\n');

        switch (select)
        {
        case 1:
            adddate();
            break;
        case 2:
            show();
            break;
        case 3:
            break;
        default:
            cout << "输入失败！" << endl;
        }
    } while (select != 3);
}

//undertype.h
#pragma once
#include <string>
class usertype
{
public:
    int position;
    char usertype;
    int num;
};

//main.cpp
#include"systemm.h"
#include"usertype.h"
int main(void) {
    try
    {
        systemm obj;
        obj.run();
    }
    catch (char* error)
    {
        cout << error;
    }
    system("PAUSE");
    return 0;
}

    充分地分析和理解问题本身，弄清要求做什么。在确定解决方案框架过程中，考虑怎样使程序结构清晰、合理、简单和易于调试，并确定每个函数的简单功能，以及函数之间的调用关系。

综上 新手写的 欢迎指出问题~