简易的学生成绩管理系统（C++实现）

最近浅显的学习了C++的基础知识，想来练练手，于是就用单链表写了最经典的小项目，存粹学习，所以就在控制台下写了，写的有点简陋，码了大概400多行。

下面上代码：

 #include <cstdlib>
 #include <iostream>
 #include <string>
 using namespace std;

 #define null NULL

 class student
 {
     private:
         friend class studentMessage;
         student *next; //节点指针
         string name; //学生姓名
         int age; //年纪
         int id; //学号
         double score[]; //三科成绩
         double total; //总分
         double average; //平均成绩
     public:
         student(string _name,int _age,int _id,double *_score)
         {
             name = _name;
             age = _age;
             id = _id;
             score[] = _score[];
             score[] = _score[];
             score[] = _score[];
             total = score[]+score[]+score[];
             average = total/;
             next = NULL;
         }
         student() //为studentMessage初始化头结点用
         {
             name = "null";
             age = ;
             id = ;
             score[]=score[]=score[]=;
             total = ;
             average = ;
             next = NULL;
         }
         ~student(){}
         void swap(student*);
 };

 void student::swap(student *q)
 {
     string _name;
     int _age,_id;
     double _score[],_total,_average;

     _name = name;
     name = q->name;
     q->name = _name;

     _age = age;
     age = q->age;
     q->age = _age;

     _id = id;
     id = q->id;
     q->id = _id;

     _score[] = score[];
     score[] = q->score[];
     q->score[] = _score[];

     _score[] = score[];
     score[] = q->score[];
     q->score[] = _score[];

     _score[] = score[];
     score[] = q->score[];
     q->score[] = _score[];

     _total = total;
     total = q->total;
     q->total = _total;

     _average = average;
     average = q->average;
     q->average = _average;
 }

 class studentMessage
 {
     private:
       student *first; //头指针
       int num; //信息中的学生人数
     public:
         studentMessage()
         {
             num = ; //初始化学生人数为0
             first = new student;  //初始化头结点
         }
         ~studentMessage(){delete first;}

         /*管理系统常规操作*/
         void Insret(void); //插入
         void Display(void); //显示
         void Delete(void); //删除
         void Search(void); //搜索
         void Change(void); //改动
         void sortByLesson1(void); //按成绩一来排序
         void sortByLesson2(void); //按成绩二来排序
         void sortByLesson3(void); //按成绩三来排序
         void sortByTotal(void); //按总分来排序
         void SearchByid(void); //按照学号查找
         void SearchByname(void); //按照姓名查找
         int menu(void); //初始的菜单
         void clear(void); //清空列表
 };

 int studentMessage::menu(void)
 {
     int ch;
     cout<<"**********************************************************************"<<endl;
     cout<<"======================================================================"<<endl;
     cout<<"***************************学生成绩管理系统***************************"<<endl;cout<<endl;
     cout<<"1.显示所有学生成绩"<<endl;
     cout<<"2.添加学生信息"<<endl;
     cout<<"3.查询学生信息"<<endl;
     cout<<"4.修改学生信息"<<endl;
     cout<<"5.删除最下面一个学生信息"<<endl;
     cout<<"6.删除所有信息"<<endl;
     cout<<"0.退出系统"<<endl;cout<<endl;
     cout<<"********************Copyright@ By Jeaven Wong**************************"<<endl;
     cout<<"======================================================================="<<endl;
     cout<<"***********************************************************************"<<endl;
     cin >> ch;
     cout<<"\n\n\n"<<endl;
     return ch;
 }

 //插入
 void studentMessage::Insret(void)
 {
     string name;
     int age;
     int id;
     double score[];
     cout<<"请输入学生姓名: ";
     cin>>name;
     cout<<"请输入学生年龄: ";
     cin>>age;
     cout<<"请输入学生学号: ";
     cin>>id;
     cout<<"下面请输入学生三门课程成绩: ";
     cout<<endl;
     cout<<"请输入第一门课的成绩: ";cin>>score[];
     cout<<"请输入第二门课的成绩: ";cin>>score[];
     cout<<"请输入第三门课的成绩: ";cin>>score[];
     cout<<endl;

     student *newstu = new student(name,age,id,score);
     student *p = first;
     while(p->next != NULL)
     {
         p = p->next;
     }
     p->next = newstu;
     newstu->next = null;
     num++;
 }

 void studentMessage::Display(void)
 {
     if(num == )
     {
         cout<<"当前记录中无学生..."<<endl;
     }

     else
     {
         student *p = first->next;
         while(p != null)
         {
             cout<<"姓名:"<<p->name<<"  ";
             cout<<"年龄:"<<p->age<<"  ";
             cout<<"学号:"<<p->id<<"  ";
             cout<<"三门课程成绩: "<<p->score[]<<" "<<p->score[]<<" "<<p->score[]<<"  ";
             cout<<"总分:"<<p->total<<"  ";
             cout<<"平均分:"<<p->average<<endl;
             p = p->next;
         }
     }
 }

 void studentMessage::Delete(void)
 {
     student *p = first;
     student *pre = first;
     while(p->next != NULL)
     {
         pre = p;
         p = p->next;
     }
     pre->next = NULL;
     delete p;
     num--;
 }

 void studentMessage::Search(void)
 {
     int temp = ;
     cout<<"请输入查找的条件，有如下选项..."<<endl;
     cout<<"按照学号查找（请输入【1】） 按照姓名查找（请输入【2】）"<<endl;
     cin>>temp;
     switch(temp)
     {
         case : SearchByid(); break;
         case : SearchByname(); break;
         default: cout<<"输入有误..."<<endl;
     }
 }

 void studentMessage::SearchByid(void)
 {
     int _id;
     int flag = ;
     cout<<"请输入待查找学生的学号：";
     cin >> _id;
     student *p = first->next;
     while(p != null)
     {
         if(p->id == _id)
         {
             flag = ;
             cout<<"下面是查找匹配结果："<<endl;
             cout<<"姓名:"<<p->name<<"  ";
             cout<<"年龄:"<<p->age<<"  ";
             cout<<"学号:"<<p->id<<"  ";
             cout<<"三门课程成绩: "<<p->score[]<<" "<<p->score[]<<" "<<p->score[]<<"  ";
             cout<<"总分:"<<p->total<<"  ";
             cout<<"平均分:"<<p->average<<endl;
         }
         p = p->next;
     }
     if(flag == )
     {
         cout<<"抱歉，记录中没有查找匹配项..."<<endl;
     }
 }

 void studentMessage::SearchByname(void)
 {
     string _name;
     int flag = ;
     cout<<"请输入待查找的学生姓名: ";
     cin >> _name;
     student *p = first->next;
     while(p != null)
     {
         if(p->name == _name)
         {
             flag = ;
             cout<<"下面是查找匹配结果："<<endl;
             cout<<"姓名:"<<p->name<<"  ";
             cout<<"年龄:"<<p->age<<"  ";
             cout<<"学号:"<<p->id<<"  ";
             cout<<"三门课程成绩: "<<p->score[]<<" "<<p->score[]<<" "<<p->score[]<<"  ";
             cout<<"总分:"<<p->total<<"  ";
             cout<<"平均分:"<<p->average<<endl;
         }
         p = p->next;
     }

     if(flag == )
     {
         cout<<"抱歉，记录中没有查找匹配项..."<<endl;
     }
 }

 void studentMessage::Change(void)
 {
     string _name;
     int flag = ,temp;
     int _id,_age;
     int course = ;
     cout<<"请输入需要改动信息的学生的姓名: ";
     cin >> _name;
     student *p = first->next;
     while(p != null)
     {
         if(p->name == _name)
         {
             flag = ;
             cout<<"该学生当前信息如下："<<endl;
             cout<<"姓名:"<<p->name<<"  ";
             cout<<"年龄:"<<p->age<<"  ";
             cout<<"学号:"<<p->id<<"  ";
             cout<<"三门课程成绩: "<<p->score[]<<" "<<p->score[]<<" "<<p->score[]<<"  ";
             cout<<"总分:"<<p->total<<"  ";
             cout<<"平均分:"<<p->average<<endl;
             cout<<"请指明哪一项需要修改..."<<endl;
             cout<<"修改学号（输入【1】） 修改年龄（输入【2】）修改成绩（输入【3】）"<<endl;
             cin >> temp;
             switch(temp)
             {
                 case :
                     {
                         cout<<"请输入新的学号：";cin>>_id;
                         p->id = _id;
                     }
                     break;
                 case :
                     {
                         cout<<"请输入新的年龄：";cin>>_age;
                         p->age = _age;
                     }
                     break;
                 case :
                     {
                         cout<<"请按指示修改课程成绩..."<<endl;
                         cout<<"是否需要修改第一门课程成绩？（需要输入【1】不需要输入【0】）"<<endl;
                         cin >> course;
                         if(course == )
                         {
                             cout<<"请输入修改后的第一门课的成绩："; cin >> p->score[];
                         }
                         course = ;

                         cout<<"是否需要修改第二门课程成绩？（需要输入【1】不需要输入【0】）"<<endl;
                         cin >> course;
                         if(course == )
                         {
                             cout<<"请输入修改后的第二门课的成绩："; cin >> p->score[];
                         }
                         course = ;

                         cout<<"是否需要修改第三门课程成绩？（需要输入【1】不需要输入【0】）"<<endl;
                         cin >> course;
                         if(course == )
                         {
                             cout<<"请输入修改后的第三门课的成绩："; cin >> p->score[];
                         }
                         course = ;

                         p->total = p->score[]+p->score[]+p->score[];
                         p->average = p->total/;

                         cout<<"修改后的信息如下： "<<endl;
                         cout<<"姓名:"<<p->name<<"  ";
                         cout<<"年龄:"<<p->age<<"  ";
                         cout<<"学号:"<<p->id<<"  ";
                         cout<<"三门课程成绩: "<<p->score[]<<" "<<p->score[]<<" "<<p->score[]<<"  ";
                         cout<<"总分:"<<p->total<<"  ";
                         cout<<"平均分:"<<p->average<<endl;
                     }
                     break;
                 default:  cout<<"输入有误..."<<endl;
             }
         }
         p = p->next;
     }
     if(flag == )
         cout<<"当前记录中没有次学生..."<<endl;
 }

 /*排序我均采用冒泡排序法，均是从小到大排序*/

 //按照科目一排序
 void studentMessage::sortByLesson1(void)
 {
     student *p = first->next;
     while(p->next != null)
     {
         student *q = p->next;
         while(q != null)
         {
             if(p->score[] > q->score[])
             {
                 p->swap(q);
             }
             q = q->next;
         }
         p = p->next;
     }
 }

 //按照科目二排序
 void studentMessage::sortByLesson2(void)
 {
     student *p = first->next;
     while(p->next != null)
     {
         student *q = p->next;
         while(q != null)
         {
             if(p->score[] > q->score[])
             {
                 p->swap(q);
             }
             q = q->next;
         }
         p = p->next;
     }
 }

 //按照科目三排序
 void studentMessage::sortByLesson3(void)
 {
     student *p = first->next;
     while(p->next != null)
     {
         student *q = p->next;
         while(q != null)
         {
             if(p->score[] > q->score[])
             {
                 p->swap(q);
             }
             q = q->next;
         }
         p = p->next;
     }
 }

 //按照总成绩排序
 void studentMessage::sortByTotal(void)
 {
     student *p = first->next;
     while(p->next != null)
     {
         student *q = p->next;
         while(q != null)
         {
             if(p->total > q->total)
             {
                 p->swap(q);
             }
             q = q->next;
         }
         p = p->next;
     }
 }

 void studentMessage::clear(void)
 {
     student *p = first->next;
     while(p != null)
     {
         first->next = p->next;
         p->next = null;
         delete p;
         p = first->next;
     }
 }

 int main()
 {
     studentMessage stulist;
     int ch;
     while(ch = stulist.menu())
     {
         switch(ch)
         {
             case : stulist.Display(); break;
             case : stulist.Insret(); break;
             case : stulist.Search(); break;
             case : stulist.Change(); break;
             case : stulist.Delete(); break;
             case : stulist.clear(); break;
             default: cout<<"请按要求输入..."<<endl;
         }
     }
     return ;
 }

下面是程序运行的结果：

初始界面：

插入信息：

连续插入后显示：

修改信息：

修改后结果：

如有错误，欢迎批评指针哈~