C++大作业——学生选课系统
创始人
2025-01-16 14:34:38
0次
C++大作业——学生选课系统
- 前言
- 1.系统概述
- 2.系统设计
- 2.1概要设计
- 2.2详细设计
- 2.2.1学生类和课程类模块设计
- 2.2.2文件信息读取和录入模块设计
- 2.2.3增删改查模块设计
- 2.2.4登入模块设计
- 2.2.5选课模块设计
- 2.2.6退选模块设计
- 3.完整代码
- 4.总结与展望
- 4.1设计总结
- 4.2设计展望
前言
本次课程设计是我第一次独自完成这样一个相对完整的项目，收获很多。但是我更想说一下本次设计中存在的不足。
首先就是在最初设计课程类和学生类时，没有考虑的那么全面，导致出现了很多冗余的接口，和公有私有混着用的情况。其次就是，虽然是用C++写的，却没有把封装体现出来，使用了很多friend友元函数也破坏了类的封装效果。
由于我最开始是在Linux系统上编写的代码，没有装中文包，所以很多注释和输出语句都是用英文写的。后来又转到Windows下的VS环境下编程，也写了一些中文的语句。导致会有中英文混用的情况，可能会影响观感。
在学习这个系统之前，建议先把学生成绩管理系统熟练掌握，掌握最基本的增删改查操作，我在本文中就不再赘述了，把重点放在选课和退选的功能讲解上。
在最后面，我也会把整个项目代码都放出来，大家可以拿去在自己的电脑上运行，应付下作业铁定是没问题的（手动狗头）。
1.系统概述
本系统是学生选课系统，主要是实现大学生的选课需求。进入系统，需要先选择用户（学生或管理员），选择管理员，需要输入对应的密码。选择完身份后，进入主菜单，会出现两个子菜单，学生菜单和课程菜单，选择相应的选项，就会进入相应的菜单，其中0选项是返回上级目录。
进入课程菜单，会看到增删改查相应的操作，还有显示全部课程信息。其中，学生用户没有对课程进行增删改的权利。管理员是超级用户，有所有操作的权利。里面的细节我们在模块的具体实现时再说。
进入学生菜单，也会看到增删改查相关的操作，还有显示全部学生的信息。不同的是，学生菜单中可以进行选课和退选的相关操作。学生用户只有查看信息，选课退选的权利，没有增删改的权利。具体细节也是放在模块中详谈。
2.系统设计
2.1概要设计
2.2详细设计
2.2.1学生类和课程类模块设计
int flag = 0; // default is student class Course { public: friend void Input_course(vector& cour); friend void Delete_course(vector& cour); friend void Modify_course(vector& cour); friend void Lookup_course(vector& cour); friend void Show_course(vector& cour); friend void Add_course(vector& cour); friend int Read_course(vector& cour); friend void Write_course(vector& cour, int n); const char* c_id() { return id; } const char* c_name() { return name; } const bool c_nature() { return nature; } Course() : id("None") , name("None") , count(0) {} public: char id[20]; char name[20]; private: bool nature; // 0 indicates elective and 1 indicates compulsory int hour; // class time int credir; // credit public: int count; // count of student 0-60 }; class Student { public: friend void Input_stu(vector& stu); friend void Delete_stu(vector& stu); friend void Modify_stu(vector& stu); friend void Lookup_stu(vector& stu); friend void Add_stu(vector& stu); friend void Show_stu(vector& stu); friend int Read_stu(vector& stu); friend void Write_stu(vector& stu, int n); friend void Select(vector& cour, vector& stu); friend void Deselect(vector& cour, vector& stu); public: char _id[20]; char _class[20]; char _name[20]; Course _cour_compulsory[2]; Course _cour_elective[1]; int _num_compulsory = 0; int _num_elective = 0; }; vector cour; vector stu; 在这个模块中，我设计了两个类来分别存储学生和课程的信息。课程的相关信息包括，课程编号、课程名、课程类型（选修/必修）、学时、学分、以及选课人数。其中规定，每门课选课人数最多不超过60人。还设计了一个构造函数，将课程的编号和课程名都定义为None。
学生类中，相关信息包括，学号、班级、姓名、所选择的必修课信息、所选的选修课信息、所选必修课数量、所选选修课数量。其中规定，每名学生所选必修课不超过两门，选修课不超过一门。
在接下来的增删查改操作中，我使用了全局变量cour，和stu这两个动态数组来分别存储课程和学生。其中全局变量flag是一个确定身份状态的变量，默认是0，学生用户。1是超级用户。
2.2.2文件信息读取和录入模块设计
void Write_course(vector& cour, int n) { fstream myfile; myfile.open("course.txt", ios::out | ios::binary); if (!myfile) { cout << "ERROR!course.txt can't open." << endl; abort(); } myfile << n << endl << endl; for (int i = 0; i < n; i++) { myfile << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t" << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl; } myfile.close(); } int Read_course(vector& cour) { cour.clear(); // clear fstream myfile; myfile.open("course.txt", ios::in | ios::binary); if (!myfile) { cout << "ERROR!course.txt can't open." << endl; abort(); } int n; // count of course myfile.seekg(0); myfile >> n; Course temp; for (int i = 0; i < n; i++) { myfile >> temp.id >> temp.name >> temp.nature >> temp.hour >> temp.credir >> temp.count; cour.push_back(temp); // push_back } myfile.close(); return n; } // 学生数据的文件操作 void Write_stu(vector& stu, int n) { fstream myfile; myfile.open("student.txt", ios::out | ios::binary); if (!myfile) { cout << "ERROR! student.txt can't open!" << endl; abort(); } myfile << n << endl << endl; for (int i = 0; i < n; i++) { myfile << stu[i]._id << "\t" << stu[i]._class << "\t" << stu[i]._name << "\t" << stu[i]._cour_compulsory[0].c_id() << "\t" << stu[i]._cour_compulsory[0].c_name() << "\t" << stu[i]._cour_compulsory[1].c_id() << "\t" << stu[i]._cour_compulsory[1].c_name() << "\t" << stu[i]._cour_elective[0].c_id() << "\t" << stu[i]._cour_elective[0].c_name() << "\t" << stu[i]._num_compulsory << "\t" << stu[i]._num_elective << endl; } myfile.close(); } int Read_stu(vector& stu) { stu.clear(); // clear fstream myfile; myfile.open("student.txt", ios::in | ios::binary); if (!myfile) { cout << "ERROR! student.txt can't open!" << endl; abort(); } int n; myfile.seekg(0); myfile >> n; Student temp; for (int i = 0; i < n; i++) { myfile >> temp._id >> temp._class >> temp._name >> temp._cour_compulsory[0].id >> temp._cour_compulsory[0].name >> temp._cour_compulsory[1].id >> temp._cour_compulsory[1].name >> temp._cour_elective[0].id >> temp._cour_elective[0].name >> temp._num_compulsory >> temp._num_elective; stu.push_back(temp); // push_back } myfile.close(); return n; } 这里，我利用了两个文件，一个course.txt来存放课程信息，一个student.txt来存放学生信息。写入文件的第一个数据一定是课程，学生的数量。在调用Write函数要传一个数量进入。
需要注意，在向文件中写入学生的信息时，我并没有将学生成员变量中，_cour_compulsory和_cour_elective数组中的信息全部写入，只是写入的学生所选课程的编号和课程名。
2.2.3增删改查模块设计
void Input_course(vector& cour) { system("cls"); cour.clear(); int i = 0; char sign = '0'; Course temp; cout << "=============== Please input the massage ===============" << endl; while (sign != 'n' && sign != 'N') { loop: cout << "ID: "; cin >> temp.id; int c = 0; while (c < i) { c++; if (!strcmp(temp.id, cour[i - c].id)) { cout << "ID repeat, please input again." << endl; goto loop; } } cout << "name of course: "; cin >> temp.name; cout << "elective or compilsory(0 or 1): "; cin >> temp.nature; cout << "class hour: "; cin >> temp.hour; cout << "credir: "; cin >> temp.credir; temp.count = 0; // the default is 0 cour.push_back(temp); // push_back cout << "whether continue(y or n): "; cin >> sign; i++; } Write_course(cour, i); // save } void Delete_course(vector& cour) { system("cls"); int n = Read_course(cour); int i = 0; char id[20]; cout << "=============== Delete the message of course ===============" << endl; cout << "please input the ID of course which you want to delete: "; cin >> id; while (i < n && strcmp(id, cour[i].id)) i++; if (i == n) { cout << "no fount." << endl; system("pause"); return; } else { if (cour[i].count) { cout << "所选人数不为零，请联系所有学生退课后，再修改课程信息。" << endl; system("pause"); return; } } for (int j = i; j < n - 1; j++) swap(cour[j], cour[j + 1]); // save char sign; cout << "whether delete(y or n): "; cin >> sign; if (sign != 'n' && sign != 'N') { cour.erase(cour.end() - 1); Write_course(cour, n - 1); cout << "=============== Delete succeed ===============" << endl; } } void Modify_course(vector& cour) { system("cls"); int n = Read_course(cour); // count of course char id[20]; int i = 0; cout << "=============== Modify course ===============" << endl; cout << "input the ID of course you want to modify: "; cin >> id; while ( i < n && strcmp(id, cour[i].id)) // i < n 要提前判断 i++; if (i == n) { cout << "no found." << endl; system("pause"); return; } else { if (cour[i].count) { cout << "所选人数不为零，请联系所有学生退课后，再修改课程信息。" << endl; system("pause"); return; } } cout << "----------------------------------------------------" << endl; cout << "ID" << "\t" << "name" << "\t" << "nature" << "\t" << "hour" << "\t" << "credir" << "\t" << "count" << endl; cout << "----------------------------------------------------" << endl; cout << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t" << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl; cout << "please reenter the message of course." << endl; cout << "name of course: "; cin >> cour[i].name; cout << "elective or compilsory(0 or 1): "; cin >> cour[i].nature; cout << "class hour: "; cin >> cour[i].hour; cout << "credir: "; cin >> cour[i].credir; // save char sign; cout << "whether save the data(y or n): "; cin >> sign; if (sign != 'n' && sign != 'N') { Write_course(cour, n); cout << "=============== Modify succeed ===============" << endl; system("pause"); } } void Lookup_course(vector& cour) { system("cls"); int n = Read_course(cour); int i = 0; char id[20]; cout << "=============== Lookup the course ===============" << endl; cout << "please input the course ID you want to seek: "; cin >> id; while (i < n && strcmp(id, cour[i].id)) i++; if (i == n) { cout << "no found." << endl; } else { cout << "---------------------------------------------" << endl; cout << "ID: " << cour[i].id << endl; cout << "name: " << cour[i].name << endl; cout << "nature: " << (cour[i].nature ? "compulsory" : "elective") << endl; cout << "class hour: " << cour[i].hour << endl; cout << "credir: " << cour[i].credir << endl; cout << "student count: " << cour[i].count << endl; } system("pause"); } void Show_course(vector& cour) { system("cls"); int n = Read_course(cour); cout << "================ display all course ================" << endl; cout << "----------------------------------------------------" << endl; cout << "ID" << "\t" << "name" << "\t" << "nature" << "\t" << "hour" << "\t" << "credir" << "\t" << "count" << endl; cout << "----------------------------------------------------" << endl; for (int i = 0; i < n; i++) { cout << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t" << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl; } system("pause"); } void Add_course(vector& cour) { system("cls"); int n = Read_course(cour); char sign = '0'; Course temp; cout << "=============== add course ===============" << endl; while (sign != 'n' && sign != 'N') { loop: cout << "ID: "; cin >> temp.id; int c = 0; while (c < n) { c++; if (!strcmp(temp.id, cour[n - c].id)) { cout << "ID repeat, please input again." << endl; goto loop; } } cout << "name of course: "; cin >> temp.name; cout << "elective or compulsory(0 or 1): "; cin >> temp.nature; cout << "class hour: "; cin >> temp.hour; cout << "credir: "; cin >> temp.credir; temp.count = 0; n++; cour.push_back(temp); cout << "whether continue(y or n): "; cin >> sign; } // save Write_course(cour, n); } Input函数只适用于第一次数据的录入，如果文件中有数据，使用Input函数会将原内容覆盖。追加课程使用函数Add。
关于课程的增删改查，没有太多要说的点，需要注意一个细节，就是如果该课程的选课人数不为零，那么是不允许对该课程进行修改或删除操作的，需要先联系选该课的学生全部退选，才可以进行修改或删除，不然就太坑了。
删除课程时，我使用了算法库中的函数swap，这个函数的参数是一个模版参数，可以交换任意类型的数据。
void Input_stu(vector& stu) { system("cls"); stu.clear(); int i = 0; char sign = '\0'; Student temp; cout << "============ please input the message ============" << endl; while (sign != 'n' && sign != 'N') { loop: cout << "student ID: "; cin >> temp._id; int c = 0; while (c < i) { c++; if (!strcmp(temp._id, stu[i - c]._id)) { cout << "ID repeat, please input again." << endl; goto loop; } } cout << "name: "; cin >> temp._name; cout << "class: "; cin >> temp._class; stu.push_back(temp); // push_back cout << "whether continue(y or n): "; cin >> sign; i++; } Write_stu(stu, i); } void Delete_stu(vector& stu) { system("cls"); int n = Read_stu(stu); int m = Read_course(cour); // number of course int i = 0; char id[20]; cout << "============ delete student ============" << endl; cout << "please input the ID of student who you want to delete: "; cin >> id; while (i < n && strcmp(id, stu[i]._id)) i++; if (i == n) { cout << "no fount." << endl; system("pause"); return; } if (stu[i]._num_compulsory) { while (stu[i]._num_compulsory > 0) { stu[i]._num_compulsory--; int c = 0; while (c < m) { if (!strcmp(stu[i]._cour_compulsory[stu[i]._num_compulsory].id, cour[c].id)) { cour[c].count--; break; } c++; } } } else if (stu[i]._num_elective) { while (stu[i]._num_elective > 0) { stu[i]._num_elective--; int c = 0; while (c < m) { if (!strcmp(stu[i]._cour_elective[stu[i]._num_elective].id, cour[c].id)) { cour[c].count--; break; } c++; } } } for (int j = i; j < n - 1; j++) swap(stu[j], stu[j + 1]); // save char sign; cout << "whether delete(y or n): "; cin >> sign; if (sign != 'n' && sign != 'N') { stu.erase(stu.end() - 1); Write_stu(stu, n - 1); Write_course(cour, m); cout << "============ delete succeed ============" << endl; system("pause"); } } void Modify_stu(vector& stu) { system("cls"); int n = Read_stu(stu); char id[20]; int i = 0; cout << "============ Modify the message of student ============" << endl; cout << "please input the ID of student who you want to modify: "; cin >> id; while (i < n && strcmp(id, stu[i]._id)) i++; if (i == n) { cout << "no found." << endl; system("pause"); return; } cout << "-------------------------------------------------------" << endl; cout << "ID: " << stu[i]._id << endl; cout << "class: " << stu[i]._class << endl; cout << "name: " << stu[i]._name << endl; cout << "-------------------------------------------------------" << endl; cout << "please reenter the message." << endl; cout << "class: "; cin >> stu[i]._class; cout << "name: "; cin >> stu[i]._name; // save char sign; cout << "whether save the data(y or n): "; cin >> sign; if (sign != 'n' && sign != 'N') { cout << "modify succeed." << endl; Write_stu(stu, n); system("pause"); } } void Lookup_stu(vector& stu) { system("cls"); int n = Read_stu(stu); Read_course(cour); int i = 0; char id[20]; cout << "============ Lookup the score of student ============" << endl; cout << "please input the ID of student you want to seek: "; cin >> id; while (i < n && strcmp(id, stu[i]._id)) i++; if (i == n) { cout << "no found." << endl; } else { cout << "ID: " << stu[i]._id << endl; cout << "class: " << stu[i]._class << endl; cout << "name: " << stu[i]._name << endl; cout << "compulsory: " << (!strcmp(stu[i]._cour_compulsory[0].id, "None") ? "None" : stu[i]._cour_compulsory[0].c_name()) << " " << (!strcmp(stu[i]._cour_compulsory[1].id, "None") ? "None" : stu[i]._cour_compulsory[1].c_name()) << endl; cout << "elective: " << (!strcmp(stu[i]._cour_elective[0].id, "None") ? "None" : stu[i]._cour_elective[0].c_name()) << endl; } system("pause"); } void Add_stu(vector& stu) { system("cls"); int n = Read_stu(stu); char sign = '0'; Student temp; cout << "============ add student ============" << endl; while (sign != 'n' && sign != 'N') { loop: cout << "student ID: "; cin >> temp._id; int c = 0; while (c < n) { c++; if (!strcmp(temp._id, stu[n - c]._id)) { cout << "ID repeat, please input again." << endl; goto loop; } } cout << "class: "; cin >> temp._class; cout << "name: "; cin >> temp._name; n++; stu.push_back(temp); // push_back cout << "whether continue(y or n): "; cin >> sign; } // save Write_stu(stu, n); } void Show_stu(vector& stu) { system("cls"); int n = Read_stu(stu); cout << "============================ diplay all student ==========================" << endl; cout << "ID" << "\t" << "class" << "\t" << "name" << "\t" << "compulsory" << "\t\t" << "elective" << endl; cout << "--------------------------------------------------------------------------" << endl; for (int i = 0; i < n; i++) { cout << stu[i]._id << "\t" << stu[i]._class << "\t" << stu[i]._name << "\t" << (!strcmp(stu[i]._cour_compulsory[0].id, "None") ? "None" : stu[i]._cour_compulsory[0].name) << " " << (!strcmp(stu[i]._cour_compulsory[1].id, "None") ? "None" : stu[i]._cour_compulsory[1].c_name()) << "\t" << (!strcmp(stu[i]._cour_elective[0].id, "None") ? "None" : stu[i]._cour_elective[0].c_name()) << endl; } system("pause"); } 以上是学生信息的增删查改，细节较多，在这里一一说明。首先，删除学生时，如果该学生选的有课，那么将学生删除后，对应课程的选课人数也应该减减；其次，打印学生所选课程时，需要先判断课程的id是否为None，如果是就打印None，表示没有选课，id不为None就说明选的有课，就打印该课程的课程名。
2.2.4登入模块设计
int choose_user() { loop: system("cls"); int c = 0; cout << "=================================================================" << endl; cout << "-------------- welcome to course selection system ---------------" << endl; cout << "please choose your identity, admin or student(1 or 2)(input 0 to exit): "; cin >> c; char passwd[20]; if (c == 1) { cout << "please input password: "; cin >> passwd; if (!strcmp(passwd, "123456")) { flag = 1; cout << "log on succeed." << endl; system("pause"); } else { cout << "password error." << endl; system("pause"); goto loop; } } else flag = 0; if (c < 0 || c > 2) { cout << "please input 0-2." << endl; system("pause"); goto loop; } return c; } void menu_course() { int c = 0; while (1) { system("cls"); cout << "============ menu of course ============" << endl; cout << " 1. input " << endl; cout << " 2. delete " << endl; cout << " 3. modify " << endl; cout << " 4. lookup " << endl; cout << " 5. add " << endl; cout << " 6. show all " << endl; cout << " 0. return " << endl; cout << "----------------------------------------" << endl; cout << "please choose your operation(0-6): "; cin >> c; switch (c) { case 1: if (flag) Input_course(cour); else { cout << "request denied." << endl; system("pause"); } break; case 2: if (flag) Delete_course(cour); else { cout << "request denied." << endl; system("pause"); } break; case 3: if (flag) Modify_course(cour); else { cout << "request denied." << endl; system("pause"); } break; case 4: Lookup_course(cour); break; case 5: if (flag) Add_course(cour); else { cout << "request denied." << endl; system("pause"); } break; case 6: Show_course(cour); break; case 0: cout << "------------ return succeed ------------" << endl; system("pause"); return; default: cout << "please input 0-6." << endl; system("pause"); break; } } } void menu_student() { int c = 0; while (1) { system("cls"); cout << "============ menu of student ============" << endl; cout << " 1. input " << endl; cout << " 2. delete " << endl; cout << " 3. modify " << endl; cout << " 4. lookup " << endl; cout << " 5. add " << endl; cout << " 6. show all " << endl; cout << " 7. select course " << endl; cout << " 8. deselect " << endl; cout << " 0. return " << endl; cout << "----------------------------------------" << endl; cout << "please choose your operation(0-6): "; cin >> c; switch (c) { case 1: if (flag) Input_stu(stu); else { cout << "request denied." << endl; system("pause"); } break; case 2: if (flag) Delete_stu(stu); else { cout << "request denied." << endl; system("pause"); } break; case 3: if (flag) Modify_stu(stu); else { cout << "request denied." << endl; system("pause"); } break; case 4: Lookup_stu(stu); break; case 5: if (flag) Add_stu(stu); else { cout << "request denied." << endl; system("pause"); } break; case 6: Show_stu(stu); break; case 7: Select(cour, stu); break; case 8: Deselect(cour, stu); break; case 0: cout << "------------ return succeed ------------" << endl; system("pause"); return; default: cout << "please input 0-6." << endl; system("pause"); break; } } } int menu_main() { int c = 0; while (1) { system("cls"); cout << "====================================================" << endl; cout << " 1. course message " << endl; cout << " 2. student message " << endl; cout << " 0. go back to higher-leve menu " << endl; cout << "choose your operation: "; cin >> c; if (c < 0 || c > 2) { cout << "please input 0-2." << endl; system("pause"); } else break; } return c; } int main() { cour.reserve(100); stu.reserve(100); while (1) { loop: if (!choose_user()) { cout << "=============== thank you for using ===============" << endl; return 0; } while (1) { switch (menu_main()) { case 1: menu_course(); break; case 2: menu_student(); break; case 0: cout << "=============== return scceed ===============" << endl; system("pause"); goto loop; default: cout << "please input 0-2." << endl; system("pause"); break; } } } return 0; } 可以看到，在进入系统后，需要先选择用户，如果选择管理员身份登入需要输入密码，选择学生身份则不用。随后会进入主菜单，有三个选项，1.课程菜单，2.学生菜单，0.返回上级目录。选择1或2就会跳转到相应的子菜单，选择0则会回到选择用户身份的界面。进入子菜单后，可以看到，课程菜单和学生菜单的前几个选项是一样的，唯一不同的是学生菜单中多了两个选项，选课和退选。
选择身份界面：
主菜单：
子菜单：
2.2.5选课模块设计
void Select(vector& cour, vector& stu) { system("cls"); int n_cour = Read_course(cour); int n_stu = Read_stu(stu); int i = 0; // student int j = 0; // course char id_c[20]; // course char id_s[20]; // student cout << "============ select system ============" << endl; cout << "please input the ID of student: "; cin >> id_s; while ( i < n_stu && strcmp(stu[i]._id, id_s)) i++; if (i == n_stu) { cout << "no found." << endl; system("pause"); return; } cout << ("please input the ID of course you want to select: "); cin >> id_c; while ( j < n_cour && strcmp(cour[j].c_id(), id_c)) j++; if (j == n_cour) { cout << "no found." << endl; system("pause"); return; } if (cour[j].count >= 60) { cout << "student number full, select failed." << endl; system("pause"); } else { if (cour[j].c_nature()) if (stu[i]._num_compulsory < 2) { int c = 0; while (c < stu[i]._num_compulsory && strcmp(cour[j].id, stu[i]._cour_compulsory[c].id)) c++; if (c < stu[i]._num_compulsory) { cout << "course repeat." << endl; system("pause"); return; } stu[i]._cour_compulsory[stu[i]._num_compulsory] = cour[j]; stu[i]._num_compulsory++; cour[j].count++; Write_course(cour, n_cour); Write_stu(stu, n_stu); cout << "select succeed." << endl; system("pause"); } else { cout << "class number upper limit, select failed." << endl; system("pause"); } else { if (stu[i]._num_elective < 1) { int c = 0; while (c < stu[i]._num_elective && strcmp(cour[j].id, stu[i]._cour_elective[c].id)) c++; if (c < stu[i]._num_elective) { cout << "course repeat." << endl; system("pause"); return; } stu[i]._cour_elective[stu[i]._num_elective] = cour[j]; stu[i]._num_elective++; cour[j].count++; Write_course(cour, n_cour); Write_stu(stu, n_stu); cout << "select succeed." << endl; system("pause"); } else { cout << "class number upper limit, select failed." << endl; system("pause"); } } } } 需要先从文件中读取到数据，然后需要输入学生id，确定身份，再输入你想选择的课程编号。如果找不到该学生或课程，就会打印no found.。找到之后，先判断的就是该课程的选课人数是否达到上限60人，如果达到，就会提示人数上限，选课失败，没达到，就进入下一环。接着判断所选择的课程类型，是必修，就判断该学生选择的必修课程数量是否达到上限，没有达到上限才会提示选课成功；是选修，就判断该学生选择的选修课数量是否达到上限，没有达到才会提示选课成功。
2.2.6退选模块设计
void Deselect(vector& cour, vector& stu) { system("cls"); int n_cour = Read_course(cour); int n_stu = Read_stu(stu); int i = 0; // student int j = 0; // course char id_c[20]; // course char id_s[20]; // student cout << "============ deselect system ============" << endl; cout << "please input the ID of student: "; cin >> id_s; while (i < n_stu && strcmp(stu[i]._id, id_s)) i++; if (i == n_stu) { cout << "no found." << endl; system("pause"); return; } cout << ("please input the ID of course you want to deselect: "); cin >> id_c; while (j < n_cour && strcmp(cour[j].c_id(), id_c)) j++; if (j == n_cour) { cout << "no found." << endl; system("pause"); return; } if (stu[i]._num_compulsory) { int c = stu[i]._num_compulsory - 1; while (c >= 0) { if (!strcmp(stu[i]._cour_compulsory[c].id, id_c)) { cour[j].count--; stu[i]._num_compulsory--; strcpy(stu[i]._cour_compulsory[c].id, "None"); strcpy(stu[i]._cour_compulsory[c].name, "None"); // 重新排序 for (; c < stu[i]._num_compulsory; c++) swap(stu[i]._cour_compulsory[c], stu[i]._cour_compulsory[c + 1]); Write_stu(stu, n_stu); Write_course(cour, n_cour); cout << "退选成功。" << endl; system("pause"); return; } c--; } if (stu[i]._cour_elective) { int c = stu[i]._num_elective - 1; while (c >= 0) { if (!strcmp(stu[i]._cour_elective[c].id, id_c)) { cour[j].count--; stu[i]._num_elective--; strcpy(stu[i]._cour_elective[c].id, "None"); strcpy(stu[i]._cour_elective[c].name, "None"); for (; c < stu[i]._num_elective; c++) swap(stu[i]._cour_elective[c], stu[i]._cour_elective[c + 1]); Write_stu(stu, n_stu); Write_course(cour, n_cour); cout << "退选成功。" << endl; system("pause"); return; } c--; } cout << "你并未选择该课程。" << endl; system("pause"); return; } } if (stu[i]._cour_elective) { int c = stu[i]._num_elective - 1; while (c >= 0) { if (!strcmp(stu[i]._cour_elective[c].id, id_c)) { cour[j].count--; stu[i]._num_elective--; strcpy(stu[i]._cour_elective[c].id, "None"); strcpy(stu[i]._cour_elective[c].name, "None"); for (; c < stu[i]._num_elective; c++) swap(stu[i]._cour_elective[c], stu[i]._cour_elective[c + 1]); Write_stu(stu, n_stu); Write_course(cour, n_cour); cout << "退选成功。" << endl; system("pause"); return; } c--; } cout << "你并未选择该课程。" << endl; system("pause"); return; } } 退选功能实现的前半部分和选课功能类似，先从文件中读取信息，输入学生id，确定身份，再输入想退选的课程id，确定要退选的课程是否存在。如果存在，接着判断该学生是否选择了该课程，只有选择了该课程，才会提示退选成功，否则提示退选失败。
退选功能中有一个细节需要尤其注意，就是每回退选课程，都需要对学生信息中的课程数组重新排序，相当于在学生信息的课程数组中，删除了这个课程。为什么要排序呢？因为我在实现选课和退选功能的时候，都是用学生成员变量中的_num_compulsory和_num_elective来做课程数组的下标的，如果不进行重新排序，会导致逻辑混乱。举个例子，现在有一个学生选了两门必修课，_cour_compulsory[0]存的是第一门课，_cour_compulsory[1]存的是第二门课，那_num_compulsory毫无疑问就是2。现在我们退选第一门课，也就是将_cour_compulsory[0]的数据改成默认值，id是None，name也是None，再对_num_compulsory减减。现在没有进行排序，此时_num_compulsory为1，再对该学生进行选课操作时，执行代码stu[i]._cour_compulsory[stu[i]._num_compulsory] = cour[j]; 会将_cour_compulsory[1]中的有效数据覆盖，而_cour_compulsory[0]中仍然是无效数据，出现逻辑错误。所以我们需要对数组重新排序，让_cour_compulsory[1]的先值给到_cour_compulsory[0]。
3.完整代码
#define _CRT_SECURE_NO_WARNINGS #include #include #include #include #include using namespace std; int flag = 0; // default is student class Course { public: friend void Input_course(vector& cour); friend void Delete_course(vector& cour); friend void Modify_course(vector& cour); friend void Lookup_course(vector& cour); friend void Show_course(vector& cour); friend void Add_course(vector& cour); friend int Read_course(vector& cour); friend void Write_course(vector& cour, int n); const char* c_id() { return id; } const char* c_name() { return name; } const bool c_nature() { return nature; } Course() : id("None") , name("None") , count(0) {} public: char id[20]; char name[20]; private: bool nature; // 0 indicates elective and 1 indicates compulsory int hour; // class time int credir; // credit public: int count; // count of student 0-60 }; class Student { public: friend void Input_stu(vector& stu); friend void Delete_stu(vector& stu); friend void Modify_stu(vector& stu); friend void Lookup_stu(vector& stu); friend void Add_stu(vector& stu); friend void Show_stu(vector& stu); friend int Read_stu(vector& stu); friend void Write_stu(vector& stu, int n); friend void Select(vector& cour, vector& stu); friend void Deselect(vector& cour, vector& stu); public: char _id[20]; char _class[20]; char _name[20]; Course _cour_compulsory[2]; Course _cour_elective[1]; int _num_compulsory = 0; int _num_elective = 0; }; vector cour; vector stu; // ========================================== Course ==================================================== // void Write_course(vector& cour, int n) { fstream myfile; myfile.open("course.txt", ios::out | ios::binary); if (!myfile) { cout << "ERROR!course.txt can't open." << endl; abort(); } myfile << n << endl << endl; for (int i = 0; i < n; i++) { myfile << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t" << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl; } myfile.close(); } int Read_course(vector& cour) { cour.clear(); // clear fstream myfile; myfile.open("course.txt", ios::in | ios::binary); if (!myfile) { cout << "ERROR!course.txt can't open." << endl; abort(); } int n; // count of course myfile.seekg(0); myfile >> n; Course temp; for (int i = 0; i < n; i++) { myfile >> temp.id >> temp.name >> temp.nature >> temp.hour >> temp.credir >> temp.count; cour.push_back(temp); // push_back } myfile.close(); return n; } void Input_course(vector& cour) { system("cls"); cour.clear(); int i = 0; char sign = '0'; Course temp; cout << "=============== Please input the massage ===============" << endl; while (sign != 'n' && sign != 'N') { loop: cout << "ID: "; cin >> temp.id; int c = 0; while (c < i) { c++; if (!strcmp(temp.id, cour[i - c].id)) { cout << "ID repeat, please input again." << endl; goto loop; } } cout << "name of course: "; cin >> temp.name; cout << "elective or compilsory(0 or 1): "; cin >> temp.nature; cout << "class hour: "; cin >> temp.hour; cout << "credir: "; cin >> temp.credir; temp.count = 0; // the default is 0 cour.push_back(temp); // push_back cout << "whether continue(y or n): "; cin >> sign; i++; } Write_course(cour, i); // save } void Delete_course(vector& cour) { system("cls"); int n = Read_course(cour); int i = 0; char id[20]; cout << "=============== Delete the message of course ===============" << endl; cout << "please input the ID of course which you want to delete: "; cin >> id; while (i < n && strcmp(id, cour[i].id)) i++; if (i == n) { cout << "no fount." << endl; system("pause"); return; } else { if (cour[i].count) { cout << "所选人数不为零，请联系所有学生退课后，再修改课程信息。" << endl; system("pause"); return; } } for (int j = i; j < n - 1; j++) swap(cour[j], cour[j + 1]); // save char sign; cout << "whether delete(y or n): "; cin >> sign; if (sign != 'n' && sign != 'N') { cour.erase(cour.end() - 1); Write_course(cour, n - 1); cout << "=============== Delete succeed ===============" << endl; } } void Modify_course(vector& cour) { system("cls"); int n = Read_course(cour); // count of course char id[20]; int i = 0; cout << "=============== Modify course ===============" << endl; cout << "input the ID of course you want to modify: "; cin >> id; while ( i < n && strcmp(id, cour[i].id)) // i < n 要提前判断 i++; if (i == n) { cout << "no found." << endl; system("pause"); return; } else { if (cour[i].count) { cout << "所选人数不为零，请联系所有学生退课后，再修改课程信息。" << endl; system("pause"); return; } } cout << "----------------------------------------------------" << endl; cout << "ID" << "\t" << "name" << "\t" << "nature" << "\t" << "hour" << "\t" << "credir" << "\t" << "count" << endl; cout << "----------------------------------------------------" << endl; cout << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t" << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl; cout << "please reenter the message of course." << endl; cout << "name of course: "; cin >> cour[i].name; cout << "elective or compilsory(0 or 1): "; cin >> cour[i].nature; cout << "class hour: "; cin >> cour[i].hour; cout << "credir: "; cin >> cour[i].credir; // save char sign; cout << "whether save the data(y or n): "; cin >> sign; if (sign != 'n' && sign != 'N') { Write_course(cour, n); cout << "=============== Modify succeed ===============" << endl; system("pause"); } } void Lookup_course(vector& cour) { system("cls"); int n = Read_course(cour); int i = 0; char id[20]; cout << "=============== Lookup the course ===============" << endl; cout << "please input the course ID you want to seek: "; cin >> id; while (i < n && strcmp(id, cour[i].id)) i++; if (i == n) { cout << "no found." << endl; } else { cout << "---------------------------------------------" << endl; cout << "ID: " << cour[i].id << endl; cout << "name: " << cour[i].name << endl; cout << "nature: " << (cour[i].nature ? "compulsory" : "elective") << endl; cout << "class hour: " << cour[i].hour << endl; cout << "credir: " << cour[i].credir << endl; cout << "student count: " << cour[i].count << endl; } system("pause"); } void Show_course(vector& cour) { system("cls"); int n = Read_course(cour); cout << "================ display all course ================" << endl; cout << "----------------------------------------------------" << endl; cout << "ID" << "\t" << "name" << "\t" << "nature" << "\t" << "hour" << "\t" << "credir" << "\t" << "count" << endl; cout << "----------------------------------------------------" << endl; for (int i = 0; i < n; i++) { cout << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t" << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl; } system("pause"); } void Add_course(vector& cour) { system("cls"); int n = Read_course(cour); char sign = '0'; Course temp; cout << "=============== add course ===============" << endl; while (sign != 'n' && sign != 'N') { loop: cout << "ID: "; cin >> temp.id; int c = 0; while (c < n) { c++; if (!strcmp(temp.id, cour[n - c].id)) { cout << "ID repeat, please input again." << endl; goto loop; } } cout << "name of course: "; cin >> temp.name; cout << "elective or compulsory(0 or 1): "; cin >> temp.nature; cout << "class hour: "; cin >> temp.hour; cout << "credir: "; cin >> temp.credir; temp.count = 0; n++; cour.push_back(temp); cout << "whether continue(y or n): "; cin >> sign; } // save Write_course(cour, n); } // ============================================ student ============================================== // void Write_stu(vector& stu, int n) { fstream myfile; myfile.open("student.txt", ios::out | ios::binary); if (!myfile) { cout << "ERROR! student.txt can't open!" << endl; abort(); } myfile << n << endl << endl; for (int i = 0; i < n; i++) { myfile << stu[i]._id << "\t" << stu[i]._class << "\t" << stu[i]._name << "\t" << stu[i]._cour_compulsory[0].c_id() << "\t" << stu[i]._cour_compulsory[0].c_name() << "\t" << stu[i]._cour_compulsory[1].c_id() << "\t" << stu[i]._cour_compulsory[1].c_name() << "\t" << stu[i]._cour_elective[0].c_id() << "\t" << stu[i]._cour_elective[0].c_name() << "\t" << stu[i]._num_compulsory << "\t" << stu[i]._num_elective << endl; } myfile.close(); } int Read_stu(vector& stu) { stu.clear(); // clear fstream myfile; myfile.open("student.txt", ios::in | ios::binary); if (!myfile) { cout << "ERROR! student.txt can't open!" << endl; abort(); } int n; myfile.seekg(0); myfile >> n; Student temp; for (int i = 0; i < n; i++) { myfile >> temp._id >> temp._class >> temp._name >> temp._cour_compulsory[0].id >> temp._cour_compulsory[0].name >> temp._cour_compulsory[1].id >> temp._cour_compulsory[1].name >> temp._cour_elective[0].id >> temp._cour_elective[0].name >> temp._num_compulsory >> temp._num_elective; stu.push_back(temp); // push_back } myfile.close(); return n; } void Input_stu(vector& stu) { system("cls"); stu.clear(); int i = 0; char sign = '\0'; Student temp; cout << "============ please input the message ============" << endl; while (sign != 'n' && sign != 'N') { loop: cout << "student ID: "; cin >> temp._id; int c = 0; while (c < i) { c++; if (!strcmp(temp._id, stu[i - c]._id)) { cout << "ID repeat, please input again." << endl; goto loop; } } cout << "name: "; cin >> temp._name; cout << "class: "; cin >> temp._class; stu.push_back(temp); // push_back cout << "whether continue(y or n): "; cin >> sign; i++; } Write_stu(stu, i); } void Delete_stu(vector& stu) { system("cls"); int n = Read_stu(stu); int m = Read_course(cour); // number of course int i = 0; char id[20]; cout << "============ delete student ============" << endl; cout << "please input the ID of student who you want to delete: "; cin >> id; while (i < n && strcmp(id, stu[i]._id)) i++; if (i == n) { cout << "no fount." << endl; system("pause"); return; } if (stu[i]._num_compulsory) { while (stu[i]._num_compulsory > 0) { stu[i]._num_compulsory--; int c = 0; while (c < m) { if (!strcmp(stu[i]._cour_compulsory[stu[i]._num_compulsory].id, cour[c].id)) { cour[c].count--; break; } c++; } } } else if (stu[i]._num_elective) { while (stu[i]._num_elective > 0) { stu[i]._num_elective--; int c = 0; while (c < m) { if (!strcmp(stu[i]._cour_elective[stu[i]._num_elective].id, cour[c].id)) { cour[c].count--; break; } c++; } } } for (int j = i; j < n - 1; j++) swap(stu[j], stu[j + 1]); // save char sign; cout << "whether delete(y or n): "; cin >> sign; if (sign != 'n' && sign != 'N') { stu.erase(stu.end() - 1); Write_stu(stu, n - 1); Write_course(cour, m); cout << "============ delete succeed ============" << endl; system("pause"); } } void Modify_stu(vector& stu) { system("cls"); int n = Read_stu(stu); char id[20]; int i = 0; cout << "============ Modify the message of student ============" << endl; cout << "please input the ID of student who you want to modify: "; cin >> id; while (i < n && strcmp(id, stu[i]._id)) i++; if (i == n) { cout << "no found." << endl; system("pause"); return; } cout << "-------------------------------------------------------" << endl; cout << "ID: " << stu[i]._id << endl; cout << "class: " << stu[i]._class << endl; cout << "name: " << stu[i]._name << endl; cout << "-------------------------------------------------------" << endl; cout << "please reenter the message." << endl; cout << "class: "; cin >> stu[i]._class; cout << "name: "; cin >> stu[i]._name; // save char sign; cout << "whether save the data(y or n): "; cin >> sign; if (sign != 'n' && sign != 'N') { cout << "modify succeed." << endl; Write_stu(stu, n); system("pause"); } } void Lookup_stu(vector& stu) { system("cls"); int n = Read_stu(stu); Read_course(cour); int i = 0; char id[20]; cout << "============ Lookup the score of student ============" << endl; cout << "please input the ID of student you want to seek: "; cin >> id; while (i < n && strcmp(id, stu[i]._id)) i++; if (i == n) { cout << "no found." << endl; } else { cout << "ID: " << stu[i]._id << endl; cout << "class: " << stu[i]._class << endl; cout << "name: " << stu[i]._name << endl; cout << "compulsory: " << (!strcmp(stu[i]._cour_compulsory[0].id, "None") ? "None" : stu[i]._cour_compulsory[0].c_name()) << " " << (!strcmp(stu[i]._cour_compulsory[1].id, "None") ? "None" : stu[i]._cour_compulsory[1].c_name()) << endl; cout << "elective: " << (!strcmp(stu[i]._cour_elective[0].id, "None") ? "None" : stu[i]._cour_elective[0].c_name()) << endl; } system("pause"); } void Add_stu(vector& stu) { system("cls"); int n = Read_stu(stu); char sign = '0'; Student temp; cout << "============ add student ============" << endl; while (sign != 'n' && sign != 'N') { loop: cout << "student ID: "; cin >> temp._id; int c = 0; while (c < n) { c++; if (!strcmp(temp._id, stu[n - c]._id)) { cout << "ID repeat, please input again." << endl; goto loop; } } cout << "class: "; cin >> temp._class; cout << "name: "; cin >> temp._name; n++; stu.push_back(temp); // push_back cout << "whether continue(y or n): "; cin >> sign; } // save Write_stu(stu, n); } void Show_stu(vector& stu) { system("cls"); int n = Read_stu(stu); cout << "============================ diplay all student ==========================" << endl; cout << "ID" << "\t" << "class" << "\t" << "name" << "\t" << "compulsory" << "\t\t" << "elective" << endl; cout << "--------------------------------------------------------------------------" << endl; for (int i = 0; i < n; i++) { cout << stu[i]._id << "\t" << stu[i]._class << "\t" << stu[i]._name << "\t" << (!strcmp(stu[i]._cour_compulsory[0].id, "None") ? "None" : stu[i]._cour_compulsory[0].name) << " " << (!strcmp(stu[i]._cour_compulsory[1].id, "None") ? "None" : stu[i]._cour_compulsory[1].c_name()) << "\t" << (!strcmp(stu[i]._cour_elective[0].id, "None") ? "None" : stu[i]._cour_elective[0].c_name()) << endl; } system("pause"); } void Select(vector& cour, vector& stu) { system("cls"); int n_cour = Read_course(cour); int n_stu = Read_stu(stu); int i = 0; // student int j = 0; // course char id_c[20]; // course char id_s[20]; // student cout << "============ select system ============" << endl; cout << "please input the ID of student: "; cin >> id_s; while ( i < n_stu && strcmp(stu[i]._id, id_s)) i++; if (i == n_stu) { cout << "no found." << endl; system("pause"); return; } cout << ("please input the ID of course you want to select: "); cin >> id_c; while ( j < n_cour && strcmp(cour[j].c_id(), id_c)) j++; // cout << cour[j].id << endl; if (j == n_cour) { cout << "no found." << endl; system("pause"); return; } if (cour[j].count >= 60) { cout << "student number full, select failed." << endl; system("pause"); } else { if (cour[j].c_nature()) if (stu[i]._num_compulsory < 2) { int c = 0; while (c < stu[i]._num_compulsory && strcmp(cour[j].id, stu[i]._cour_compulsory[c].id)) c++; if (c < stu[i]._num_compulsory) { cout << "course repeat." << endl; system("pause"); return; } stu[i]._cour_compulsory[stu[i]._num_compulsory] = cour[j]; // cout << stu[i]._cour_compulsory[stu[i]._num_compulsory].id << endl; // cout << stu[i]._cour_compulsory[stu[i]._num_compulsory].c_name() << endl; stu[i]._num_compulsory++; cour[j].count++; Write_course(cour, n_cour); Write_stu(stu, n_stu); // cout << stu[i]._cour_compulsory[stu[i]._num_compulsory].id << endl; cout << "select succeed." << endl; system("pause"); } else { cout << "class number upper limit, select failed." << endl; system("pause"); } else { if (stu[i]._num_elective < 1) { int c = 0; while (c < stu[i]._num_elective && strcmp(cour[j].id, stu[i]._cour_elective[c].id)) c++; if (c < stu[i]._num_elective) { cout << "course repeat." << endl; system("pause"); return; } stu[i]._cour_elective[stu[i]._num_elective] = cour[j]; stu[i]._num_elective++; cour[j].count++; Write_course(cour, n_cour); Write_stu(stu, n_stu); cout << "select succeed." << endl; system("pause"); } else { cout << "class number upper limit, select failed." << endl; system("pause"); } } } } void Deselect(vector& cour, vector& stu) { system("cls"); int n_cour = Read_course(cour); int n_stu = Read_stu(stu); int i = 0; // student int j = 0; // course char id_c[20]; // course char id_s[20]; // student cout << "============ deselect system ============" << endl; cout << "please input the ID of student: "; cin >> id_s; while (i < n_stu && strcmp(stu[i]._id, id_s)) i++; if (i == n_stu) { cout << "no found." << endl; system("pause"); return; } cout << ("please input the ID of course you want to deselect: "); cin >> id_c; while (j < n_cour && strcmp(cour[j].c_id(), id_c)) j++; if (j == n_cour) { cout << "no found." << endl; system("pause"); return; } if (stu[i]._num_compulsory) { int c = stu[i]._num_compulsory - 1; while (c >= 0) { if (!strcmp(stu[i]._cour_compulsory[c].id, id_c)) { cour[j].count--; stu[i]._num_compulsory--; strcpy(stu[i]._cour_compulsory[c].id, "None"); strcpy(stu[i]._cour_compulsory[c].name, "None"); // 重新排序 for (; c < stu[i]._num_compulsory; c++) swap(stu[i]._cour_compulsory[c], stu[i]._cour_compulsory[c + 1]); Write_stu(stu, n_stu); Write_course(cour, n_cour); cout << "退选成功。" << endl; system("pause"); return; } c--; } if (stu[i]._cour_elective) { int c = stu[i]._num_elective - 1; while (c >= 0) { if (!strcmp(stu[i]._cour_elective[c].id, id_c)) { cour[j].count--; stu[i]._num_elective--; strcpy(stu[i]._cour_elective[c].id, "None"); strcpy(stu[i]._cour_elective[c].name, "None"); for (; c < stu[i]._num_elective; c++) swap(stu[i]._cour_elective[c], stu[i]._cour_elective[c + 1]); Write_stu(stu, n_stu); Write_course(cour, n_cour); cout << "退选成功。" << endl; system("pause"); return; } c--; } cout << "你并未选择该课程。" << endl; system("pause"); return; } } if (stu[i]._cour_elective) { int c = stu[i]._num_elective - 1; while (c >= 0) { if (!strcmp(stu[i]._cour_elective[c].id, id_c)) { cour[j].count--; stu[i]._num_elective--; strcpy(stu[i]._cour_elective[c].id, "None"); strcpy(stu[i]._cour_elective[c].name, "None"); for (; c < stu[i]._num_elective; c++) swap(stu[i]._cour_elective[c], stu[i]._cour_elective[c + 1]); Write_stu(stu, n_stu); Write_course(cour, n_cour); cout << "退选成功。" << endl; system("pause"); return; } c--; } cout << "你并未选择该课程。" << endl; system("pause"); return; } } // =========================================== menu ========================================== // int choose_user() { loop: system("cls"); int c = 0; cout << "=================================================================" << endl; cout << "-------------- welcome to course selection system ---------------" << endl; cout << "please choose your identity, admin or student(1 or 2)(input 0 to exit): "; cin >> c; char passwd[20]; if (c == 1) { cout << "please input password: "; cin >> passwd; if (!strcmp(passwd, "123456")) { flag = 1; cout << "log on succeed." << endl; system("pause"); } else { cout << "password error." << endl; system("pause"); goto loop; } } else flag = 0; if (c < 0 || c > 2) { cout << "please input 0-2." << endl; system("pause"); goto loop; } return c; } void menu_course() { int c = 0; while (1) { system("cls"); cout << "============ menu of course ============" << endl; cout << " 1. input " << endl; cout << " 2. delete " << endl; cout << " 3. modify " << endl; cout << " 4. lookup " << endl; cout << " 5. add " << endl; cout << " 6. show all " << endl; cout << " 0. return " << endl; cout << "----------------------------------------" << endl; cout << "please choose your operation(0-6): "; cin >> c; switch (c) { case 1: if (flag) Input_course(cour); else { cout << "request denied." << endl; system("pause"); } break; case 2: if (flag) Delete_course(cour); else { cout << "request denied." << endl; system("pause"); } break; case 3: if (flag) Modify_course(cour); else { cout << "request denied." << endl; system("pause"); } break; case 4: Lookup_course(cour); break; case 5: if (flag) Add_course(cour); else { cout << "request denied." << endl; system("pause"); } break; case 6: Show_course(cour); break; case 0: cout << "------------ return succeed ------------" << endl; system("pause"); return; default: cout << "please input 0-6." << endl; system("pause"); break; } } } void menu_student() { int c = 0; while (1) { system("cls"); cout << "============ menu of student ============" << endl; cout << " 1. input " << endl; cout << " 2. delete " << endl; cout << " 3. modify " << endl; cout << " 4. lookup " << endl; cout << " 5. add " << endl; cout << " 6. show all " << endl; cout << " 7. select course " << endl; cout << " 8. deselect " << endl; cout << " 0. return " << endl; cout << "----------------------------------------" << endl; cout << "please choose your operation(0-6): "; cin >> c; switch (c) { case 1: if (flag) Input_stu(stu); else { cout << "request denied." << endl; system("pause"); } break; case 2: if (flag) Delete_stu(stu); else { cout << "request denied." << endl; system("pause"); } break; case 3: if (flag) Modify_stu(stu); else { cout << "request denied." << endl; system("pause"); } break; case 4: Lookup_stu(stu); break; case 5: if (flag) Add_stu(stu); else { cout << "request denied." << endl; system("pause"); } break; case 6: Show_stu(stu); break; case 7: Select(cour, stu); break; case 8: Deselect(cour, stu); break; case 0: cout << "------------ return succeed ------------" << endl; system("pause"); return; default: cout << "please input 0-6." << endl; system("pause"); break; } } } int menu_main() { int c = 0; while (1) { system("cls"); cout << "====================================================" << endl; cout << " 1. course message " << endl; cout << " 2. student message " << endl; cout << " 0. go back to higher-leve menu " << endl; cout << "choose your operation: "; cin >> c; if (c < 0 || c > 2) { cout << "please input 0-2." << endl; system("pause"); } else break; } return c; } // ============================================================================================================= // int main() { cour.reserve(100); stu.reserve(100); while (1) { loop: if (!choose_user()) { cout << "=============== thank you for using ===============" << endl; return 0; } while (1) { switch (menu_main()) { case 1: menu_course(); break; case 2: menu_student(); break; case 0: cout << "=============== return scceed ===============" << endl; system("pause"); goto loop; default: cout << "please input 0-2." << endl; system("pause"); break; } } } return 0; } 大家可以自行复制运行。
4.总结与展望
4.1设计总结
本次课程设计是我第一次独自完成这样一个相对完整的项目，收获很多。但是我更想说一下本次设计中存在的不足。首先就是在最初设计课程类和学生类时，没有考虑的那么全面，导致出现了很多冗余的接口，和公有私有混着用的情况。其次就是，虽然是用C++写的，却没有把封装体现出来，使用了很多friend友元函数也破坏了类的封装效果。
4.2设计展望
接下来，我打算再优化一下这个系统，首先就是从友元函数入手，减少友元。我打算将增删改查都设计成成员函数，这样函数的命名也会方便很多。
然后就是将用到字符串的地方，全部使用string代替，可以避免使用很多C中的字符串操作函数。我还准备设计一下学生类和课程类的输入输出流重载，这样也能让代码量减少很多。
以上就是我对本次程序设计实习的设计展望。谢谢大家的支持！
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