C++二进制文件读写

简单二进制文件读写，多文件

/Demo9.1.cpp/

1 #include <iostream>
 2 #include <fstream>
 3 #include <string>
 4 #include <windows.h>
 5 #include "UserList.h"
 6 using namespace std;
 7 
 8 int showMain()
 9 {
10     system("cls");
11     cout<<"1.增加"<<endl;
12     cout<<"2.删除"<<endl;
13     cout<<"3.修改"<<endl;
14     cout<<"4.查询"<<endl;
15     cout<<"0.退出"<<endl;
16     cout<<"请选择：";
17     cin.sync();
18     int c;
19     cin>>c;
20     return c;
21 }
22 
23 void ADD(UserList &L)
24 {
25     cout<<"input:"<<endl;
26     string id,name,password;
27     cin>>id>>name>>password;
28     User u(id,name,password);
29     L.Add(u);
30 }
31 void DEL(UserList &L)
32 {cerr<<"功能未定义"<<endl;Sleep(512);}
33 void REV(UserList &L)
34 {cerr<<"功能未定义"<<endl;Sleep(512);}
35 void SEE(UserList &L)
36 {
37     cout<<"表："<<endl;
38     for(int i=0;i<L.getN();i++)
39         L.display(i);
40     cout<<endl;
41     system("pause");
42 }
43 
44 int main()
45 {
46     UserList L;
47 //    User admin("0","admin","admin");
48 //    L.Add(admin);
49     bool flag=true;
50     while(flag)
51     {
52         switch(showMain())
53         {
54             case 0:flag=false;break;
55             case 1:ADD(L);break;
56             case 2:DEL(L);break;
57             case 3:REV(L);break;
58             case 4:SEE(L);break;
59             default:break;
60         }
61     }
62     Sleep(256);
63     return 0;
64 }

Demo9.1.cpp

/UserList.h/

1 #include <fstream>
 2 #include "User.h"
 3 using namespace std;
 4 
 5 class UserList
 6 {
 7 protected:
 8     User *List;
 9     int N,nMax;
10     string FileName;
11 public:
12     UserList(/*string Fn=""*/)
13     {
14         List=new User[32];
15         N=0;
16         nMax=32;
17     //    FileName=Fn;
18         FileName="D:\#\Users.dat";
19         readFile();
20     }
21     //
22     bool readFile()
23     {
24         ifstream fin(FileName.c_str(),ios::binary);
25         if(!fin)
26             return false;
27         fin.seekg(0,ios::end);
28         int FileLen=fin.tellg(),len=sizeof(User);
29         fin.seekg(0,ios::beg);
30         fin.read((char *)List,(N = FileLen<nMax*len?FileLen/len:nMax)*len);
31         fin.close();
32         /*
33         printf("*%d*",N);
34         for(int i=0;i<N;i++)
35             display(i);
36         cout<<endl;
37         */
38         return true;
39     }
40     int Add(User u)
41     {
42         if(N<nMax)
43         {
44             List[N]=u;
45             ofstream fout(FileName.c_str(),ios::app|ios::binary);
46             int len=sizeof(User);
47             fout.seekp((N)*len);
48             fout.write((char *)&List[N],len);
49             fout.close();
50 
51             N++;
52             return N-1;
53         }//'else-重分配内存'或'使用vector容器'解决数据溢出
54         return -1;
55     }
56     void idFind(string id)
57     {
58     }
59     void nameFind(string name)
60     {
61     }
62     void display(int i)
63     {cout<<"ID:"<<List[i].id<<endl<<"Name:"<<List[i].name<<endl<<"Password:"<<List[i].password<<endl;}
64     int getN()
65     {return N;}
66 };

UserList.h

/User.h/

1 #include <iostream>
 2 #include <string>
 3 using namespace std;
 4 
 5 class User
 6 {
 7     friend class UserList;
 8 protected:
 9     string id;
10     string name;
11     string password;
12 public:
13     User(string id="",string name="",string password=""):id(id),name(name),password(password)
14     {}
15 };

User.h

后序慢慢补充
原文链接: https://www.cnblogs.com/Leroscox/p/6137347.html

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