C++学生成绩管理系统，用结构体做，有没有人会？

Question

Answer 1

参考：

#define  _CRT_SECURE_NO_WARNINGS
 
#include<iostream>
using namespace std;
#include<string.h>
#include<fstream>
 
class student
{
private:
    student* next;
public:
    char stu_num[15];                  //学号
    char stu_name[30];                //姓名
    float stu_score;                      //成绩
 
    void afterInsert(student *p);//在该节点后插入一个节点
    void afterDelete();//在该节点后删除一个节点
    
    student *getNext()//获得下一个节点的指针
    { 
        return next; 
    }
 
    /***********查询学生信息************/
    void getMage();
 
    /******学生信息修改******/
    void changeMage(int n, char *ptr);
    void changegrade(float p);
 
    /******构造*****/
    student(char *num, char *name, float score);
    student();
};
 
void student::changegrade(float p)
{
    stu_score = p;
}
 
student::student()           //构造
{
    strcpy(stu_num, "\0");
    strcpy(stu_name, "\0");
    stu_score = 0;
    next = '\0';
}
 
student::student(char *num, char *name, float score)
{
    strcpy(stu_num, num);
    strcpy(stu_name, name);
    stu_score = score;
    next = '\0';
}
 
void student::afterInsert(student *p)//插入节点
{
    p->next = next;
    next = p;
}
 
void student::afterDelete()        //删除节点
{
    student *p = next;
    next = p->next;
    delete p;
}
 
void student::getMage()             //获得信息
{
    cout << "学号：" << stu_num << "      姓名：" << stu_name;
    cout << "      c++成绩：" << stu_score << endl;
}
 
void student::changeMage(int n, char *ptr)
{
    switch (n)
    {
    case 1: strcpy(stu_num, ptr); 
        break;
    case 2: strcpy(stu_name, ptr);
    }
}
 
//建立链表函数
void  construct_list(student *tail)
{
    student *p = new student;
    char very[20];
    float achieve;
    cout << "请输入学号:" << endl;
    cin >> very;
    p->changeMage(1, very);
    cout << "请输入姓名：" << endl;
    cin >> very;
    p->changeMage(2, very);
    cout << "请输入c++成绩：" << endl;
    cin >> achieve;
    p->changegrade(achieve);
    system("cls");
    cout << "信息输入完毕" << endl;
 
    for (; tail->getNext() != '\0';)
    {
        tail = tail->getNext();
    }
 
    tail->afterInsert(p);
}
 
/*********查询信息*********/
student *findmege(student *head)
{
loop:
    cout << "1--按姓名查询           2--按学号查询              q--返回上一级菜单" << endl;
    char p[5], ptr[20];
    student *mid = head;
    cin >> p;
 
    if (p[0] != '1'&&p[0] != '2'&&p[0] != 'q' || strlen(p)>1)
    {
        system("cls");
        cout << "对不起，你的输入有误，请重新输入！" << endl;
        goto loop;
    }
 
    switch (p[0])
    {
    case '1':
    {
        system("cls");
        cout << "请输入要查找的姓名：" << endl;
        cin >> ptr;
 
        for (; strcmp(ptr, mid->stu_name) != 0; mid = mid->getNext())
        {
            if (mid->getNext() == '\0')
            {
                cout << "对不起，你要查找的人不存在，请确认你的输入是否正确！" << endl;
                goto loop;
            }
        }
        return mid;
    }
    case '2':
    {
        system("cls");
        cout << "请输入您要查找的学号：" << endl;
        cin >> ptr;
        for (; strcmp(ptr, mid->stu_num) != 0; mid = mid->getNext())
        {
            if (mid->getNext() == '\0')
            {
                cout << "对不起，您要查找的内容不存在，请确认您的输入是否正确！" << endl;
                goto loop;
            }
        }
        return mid;
    }
    case 'q': 
    {
        return '\0';
    }
    default:
    {
        system("cls");
        cout << "对不起，您的输入有误，请重新输入！" << endl;
        goto loop;
    }
    }
}
 
/******************删除链表 节点***********************/
void delete_list(student *head)
{
    student *p = '\0';
    char selet[4];
    system("cls");
    cout << "在删除前，系统会根据您的提示找到您要删除的学生信息！" << endl;
    p = findmege(head);
    if (p != '\0')
    {
        cout << "确认要删除吗（yes/任意键返回）" << endl;
        cin >> selet;
 
        if (strcmp(selet, "yes") == 0)
        {
            for (; head->getNext() != p; head = head->getNext());
            head->afterDelete();
            system("cls");
            cout << "该信息删除成功！" << endl;
        }
    }
}
 
/*******************修改节点信息********************/
void change_info(student *head)
{
    system("cls");
    cout << "在您修改前，系统会根据您提供的信息找的您要修改的信息：" << endl;
    student *p = '\0';
 
    float achieve;
    p = findmege(head);
    if (p != '\0')
    {
        cout << "请输入c++成绩:" << endl;
        cin >> achieve;
        p->changegrade(achieve);
        system("cls");
        cout << "修改成功!" << endl;
    }
 
}
 
/**************输出学生成绩信息**************/
void output(student *head)
{
    system("cls");
    cout << "1-查看指定学生信息；2-查看所有学生信息；3-分段输出学生信息" << endl;
    char ch;
    int n = 0;
    head = head->getNext();
    cin >> ch;
    switch (ch)
    {
    case '1': 
        head = findmege(head);
        if (head == '\0')
        {
            break;
        }
        head->getMage();
        break;
    case '2': 
    while (head)
    {
        head->getMage();
        head = head->getNext();
    }
    break;
    case '3': 
        cout << "a-60分以下；b-60~70分之间；c-70~80分之间；d-80~90分之间；e-90~100分之间：" << endl;
        cin >> ch;
        switch (ch)
        {
        case 'a':
        while (head)
        {
            if (head->stu_score <= 60)
            {
                head->getMage();
                n++;
            }
            head = head->getNext();
        }
         break;
        case 'b': 
        while (head)
        {
            if (head->stu_score>60 && head->stu_score <= 70) 
            { 
                head->getMage();
                n++; 
            }
            head = head->getNext();
        }
        break;
        case 'c': 
        while (head)
        {
            if (head->stu_score>70 && head->stu_score <= 80)
            { 
                head->getMage(); 
                n++; 
            }
            head = head->getNext();
        }
        break;
        case 'd': 
        while (head)
        {
            if (head->stu_score>80 && head->stu_score <= 90)
            {
                head->getMage();
                n++;
            }
            head = head->getNext();
        }
        break;
        case 'e': 
        while (head)
        {
            if (head->stu_score>90 && head->stu_score <= 100)
            { 
                head->getMage();
                n++;
            }
            head = head->getNext();
        }
        }
        if (n == 0)
        {
            cout << "该分段内没有您要找的学生信息" << endl;
        }
    }
}
 
/*****************主菜单************************/
void mainmenu(student *head)
{
    char selet[10];
    int n = 1;
    ofstream outfile;
    ifstream infile;
    student *p, *ptr;
    student *test = head, *mid;
    cout << "*************************欢迎进入学生信息管理系统*************************" << endl;
    do {
        cout << "**************************************************************************" << endl;
        cout << "1.插入信息；   2.删除信息；  3.修改信息； 4.查看信息； 5.保存  " << endl;
        cout << "按'q'键退出      " << endl;
        cout << "**************************************************************************" << endl;
        cin >> selet;
        if (((selet[0]<'1' || selet[0]>'6') && selet[0] != 'q') || strlen(selet)>1)
        {
            system("cls");
            cout << "您的输入有误，请重新输入！" << endl;
            break;
        }
        switch (selet[0])
        {
 
        case '1':
            construct_list(head);
            break; 
        case '2': 
            delete_list(head); 
            break;
        case '3': 
            change_info(head);
            break;
        case '4': 
            output(head);
            break;
        case '5':  
            outfile.open("students.txt", ios::out | ios::app);
            for (p = head->getNext(); p != '\0'; p = p->getNext())
            {
                outfile << p->stu_name << ' ';
                outfile << p->stu_num << ' ';
                outfile << p->stu_score << ' ';
                outfile << endl;
            }
            outfile.close();
            system("cls");
            cout << "保存成功！" << endl;
            break;
        case 'q': 
            break;
        }
    } while (selet[0] != 'q');
}
 
void main()
{
    student head;
    mainmenu(&head);
}