1 //**************************************************************************************************************
  2 //作者：
  3 //日期：2018/3/19
  4 //学号：
  5 //题号：5-5
  6 //题目：编写一个程序，实现以下功能：
  7
  8 //      1)输入一系列的学生数据（包括学生的学号、姓名和成绩等基本信息），将学生信息写入二进制文件student.dat中。
  9
 10 //      2)从student.dat文件中读出这些数据并显示出来。
 11
 12 //      3)在student.dat文件中按姓名进行查询，如输入“李”，则将所有姓“李”的学生的   数据显示出来。
 13
 14 //      4)可对指定学生的数据进行修改。
 15
 16 //      5)可以删除指定的学生数据。
 17
 18 //**************************************************************************************************************
 19
 20
 21
 22 #include<iostream>
 23 #include<fstream>
 24 #include<stdlib.h>
 25 #include<cstring>
 26 using namespace std;
 27 struct Std
 28 {
 29     char name[20];
 30     char id[20];
 31     char score[5];
 32 };
 33 void getinfo(char filename[]);
 34 void showinfo(char filename[]);
 35 void searchinfo(char filename[]);
 36 void editinfo(char filename[]);
 37 void deleteinfo(char filename[]);
 38
 39 int main()
 40 {
 41     fstream student;
 42     char choice;
 43     char filename[20];
 44     cout << "Please type in the filename:";
 45     cin.getline(filename,20);
 46     cout << endl;
 47     while(true)
 48     {
 49         cout << "Please type down the manipulation code:\nA.Input information\tB.Show information\tC.Search\tD.Edit\tE.Delete\tF.Exit\n";
 50         cout << endl;
 51         cin >> choice;
 52         switch(choice)
 53         {
 54             case'A':
 55             case'a':getinfo(filename);break;
 56             case'B':
 57             case'b':showinfo(filename);break;
 58             case'C':
 59             case'c':searchinfo(filename);break;
 60             case'D':
 61             case'd':editinfo(filename);break;
 62             case'E':
 63             case'e':deleteinfo(filename);break;
 64             case'F':
 65             case'f':exit(0);
 66         }
 67         cout << endl;
 68     }
 69     return 0;
 70 }
 71
 72 void getinfo(char filename[])
 73 {
 74     fstream student;
 75     student.open(filename,ios::out|ios::binary);
 76     if(!student)
 77     {
 78         cout << "Error!";
 79         exit(0);
 80     }
 81     int count;
 82     cout << "How many student's information would you like to input?";
 83     cin >> count;
 84     Std *Student;
 85     Student = new struct Std[count];
 86     for(int i=0;i<count;i++)
 87     {
 88         cout << "Please input student "<<i+1<<" 's name:";
 89         cin.get();
 90         cin.getline(Student[i].name,20);
 91         cout << "Please input student "<<i+1<<" 's id:";
 92         cin.getline(Student[i].id,20);
 93         cout << "Please input student "<<i+1<<" 's score:";
 94         cin >> Student[i].score;
 95         student.write((char*)&Student[i],sizeof(Student[i]));
 96     }
 97     cout << "Done.";
 98     delete[]Student;
 99     student.close();
100 }
101
102 void showinfo(char filename[])
103 {
104     fstream student;
105     student.open(filename,ios::in|ios::binary);
106     if(!student)
107     {
108         cout << "Error!";
109         exit(0);
110     }
111     Std Student;
112     student.read((char*)&Student,sizeof(Student));
113     while(!student.eof())
114     {
115         cout << "name:";
116         cout << Student.name <<endl;
117         cout << "id:";
118         cout << Student.id <<endl;
119         cout << "score:";
120         cout << Student.score <<endl;
121         student.read((char*)&Student,sizeof(Student));
122     }
123     cout << "Above are all the information."<<endl;
124     student.close();
125 }
126
127 void searchinfo(char filename[])
128 {
129     fstream student;
130     Std Student;
131     student.open(filename,ios::in|ios::binary);
132     if(!student)
133     {
134         cout << "Error!";
135         exit(0);
136     }
137     char ch,Name;
138     cout << "Please input the first name:";
139     cin >> Name;
140     long position = student.tellg();
141     cout << "position:"<<position<<endl;
142     student.seekg(0L,ios::beg);
143     student.get(ch);
144     cout << "ch:"<<ch<<endl;
145     //cout << "\nch:"<<ch<<endl;
146     position = student.tellg();
147     cout << "position:"<<position<<endl;
148     student.seekg(0L,ios::beg);
149     long current_pos = 0L;
150     while(!student.eof())
151     {
152         if(ch == Name)
153         {
154             cout << "ch:"<<ch<<endl;
155             student.read((char*)&Student,sizeof(Student));
156             long position;
157             position = student.tellg();
158             cout << "position:"<<position<<endl;
159             cout << "name:";
160             cout << Student.name <<endl;
161             cout << "id:";
162             cout << Student.id <<endl;
163             cout << "score:";
164             cout << Student.score <<endl;
165             student.seekg(-(sizeof(Student)),ios::cur);
166             position = student.tellg();
167             cout << "position:"<<position<<endl;
168         }
169         current_pos = current_pos + sizeof(Student);
170         student.seekg(current_pos,ios::cur);
171   //      long position = student.tellg();
172  //           cout << "position:"<<position<<endl;
173         //student.seekg(1L,ios::cur);
174         //cin.ignore();
175         //position = student.tellg();
176         //cout << "position:"<<position<<endl;
177  //       student.get(ch);
178  //       position = student.tellg();
179  //           cout << "position:"<<position<<endl;
180   //      student.seekg(-sizeof(ch),ios::cur);
181    //     position = student.tellg();
182 //s            cout << "position:"<<position<<endl;
183     }
184     cout << "Above are all the information that you are looking for."<<endl;
185     student.close();
186 }
187
188 void editinfo(char filename[])
189 {
190     fstream student;
191     Std Student;
192     student.open(filename,ios::in|ios::out|ios::binary);
193     if(!student)
194     {
195         cout << "Error!";
196         exit(0);
197     }
198     char editid[20];
199     cout << "Please input the id of the student whose information needs to be edited:";
200     cin >> editid;
201     student.seekg(0L,ios::beg);
202     student.seekg(sizeof(Student.name),ios::beg);
203     student.seekp(0L,ios::beg);
204     student.read((char*)&Student.id,sizeof(Student.id));
205     while(!student.eof())
206     {
207         if(strcmp(editid,Student.id)==0)
208         {
209             student.seekg(-sizeof(Student.id)-sizeof(Student.name),ios::cur);
210             student.read((char*)&Student,sizeof(Student));
211             cout << "The information of the student:"<<endl;
212             cout << "name:"<<Student.name<<endl;
213             cout << "id:"<<Student.id<<endl;
214             cout << "score:"<<Student.score<<endl;
215             cout << "Now please input the new information:";
216             cout << "name:";
217             cin >> Student.name;
218             cout << "id:";
219             cin >> Student.id;
220             cout << "score:";
221             cin >> Student.score;
222             student.write((char*)&Student,sizeof(Student));
223             break;
224         }
225         student.seekg(sizeof(Student),ios::cur);
226         student.seekp(sizeof(Student),ios::cur);
227     }
228     cout << "Done.";
229     student.close();
230 }
231
232 void deleteinfo(char filename[])
233 {
234     fstream student;
235     Std Student;
236     student.open(filename,ios::in|ios::out|ios::binary);
237     if(!student)
238     {
239         cout << "Error!";
240         exit(0);
241     }
242     char deleid[20];
243     cout << "Please input the id of the student whose information needs to be erased:";
244     cin >> deleid;
245     student.seekg(0L,ios::beg);
246     student.seekg(sizeof(Student.name),ios::beg);
247     student.seekp(0L,ios::beg);
248     student.read((char*)&Student.id,sizeof(Student.id));
249     while(!student.eof())
250     {
251         if(strcmp(deleid,Student.id)==0)
252         {
253             student.seekg(-sizeof(Student.id)-sizeof(Student.name),ios::cur);
254             student.read((char*)&Student,sizeof(Student));
255             cout << "The information of the student:"<<endl;
256             cout << "name:"<<Student.name<<endl;
257             cout << "id:"<<Student.id<<endl;
258             cout << "score:"<<Student.score<<endl;
259             cout << "type 'd' to delete this student's information:";
260             char code;
261             cin >> code;
262             if(code == 'd')
263             {
264                 strcpy(Student.name,0);
265                 strcpy(Student.id,0);
266                 strcpy(Student.score,0);
267             }
268             student.write((char*)&Student,sizeof(Student));
269             break;
270         }
271         student.seekg(sizeof(Student),ios::cur);
272         student.seekp(sizeof(Student),ios::cur);
273     }
274     cout << "Done.";
275     student.close();
276 }