#include<iostream>
#include<fstream>
#include<process.h>
#include<string.h>
#include<stdlib.h>
#include<conio.h>
using namespace std;
  
class Student
{
 public:
  char name[20];
  char Id[20];
  char sex[4];
  int age;
  int Cnum;      
  int Mnum;      
  int Enum;      
  int math;
  int sum;        
  int average;
  Student * Next;
  void Input()
  {
   cout<<"\t\t请输入学生的姓名：";  cin>>name;
   cout<<"\t\t请输入学生的学号：";  cin>>Id;
   cout<<"\t\t请输入学生的性别：";  cin>>sex;
   cout<<"\t\t请输入学生的年龄：";  cin>>age;
   cout<<"\t\t请输入C++课程的成绩：";  cin>>Cnum;
   cout<<"\t\t请输入汇编课程的成绩：";  cin>>Mnum;
   cout<<"\t\t请输入嵌入式操作系统课程的成绩：";  cin>>Enum;
   cout<<"\t\t请输入数学成绩：";  cin>>math;
   sum=Cnum+Mnum+Enum+math;
   average=sum/4;
  }
  void ReadFile(istream & in)
  {
   in>>name>>Id>>sex>>age>>Cnum>>Mnum>>Enum>>math>>sum>>average;
  }
  void Show()
  {
   cout<<"姓名:"<<name<<endl<<"学号:"<<Id<<endl<<"性别:"<<sex<<endl<<"年龄:"<<age<<endl<<"C++:"<<Cnum<<endl
    <<"汇编:"<<Mnum<<endl<<"嵌入式操作系统："<<Enum<<endl<<"数学:"<<math<<endl<<"总成绩:"<<sum<<endl<<"平均成绩:"<<average<<endl<<endl<<endl;
  }
};
  
class Studentmassage
{
 public:
  Studentmassage();
  ~Studentmassage();
  void ShowMenu();
  void Find();
  void Save();
  void ModifyItem();
  void RemoveItem();
  void Swap(Student *,Student *);
  void Sort();
  void t();   //statistic
  //void Unpass();
  int ListCount();
  //void Average();
  void Display()
  {
   for(Student * p=Head->Next;p!=End;p=p->Next)
    p->Show();
   cout<<"输入任意字符！继续……";
   getch();
  }
  void AddItem()
  {
   End->Input();
   End->Next=new Student;
   End=End->Next;
   cout<<"添加成功!"<<endl;
   cout<<"输入任意字符！继续……";
   getch();
  }
 private:
  Student * Head,* End;
  ifstream in;
  ofstream out;
  Student *FindItem(char * name)
  {
   for(Student * p=Head;p->Next!=End;p=p->Next)
    if(!strcmp(p->Next->name,name))return p;
    return NULL;
  }
  Student *FindID(char * Id)
  {
   for(Student * p=Head;p->Next!=End;p=p->Next)
    if(!strcmp(p->Next->Id,Id))return p;
    return NULL;
  }
};
  
Studentmassage::Studentmassage()
{
  Head=new Student;
  Head->Next=new Student;
  End=Head->Next;
  in.open("sort.txt");
  if(!in)
   {
   cout<<"这是一个新系统，无学生信息。请先输入。"<<endl; }
  else
  {
   while(!in.eof())
   {
    End->ReadFile(in);
    if(End->name[0]=='\0')break;
    End->Next=new Student;
    End=End->Next;
   }
   in.close();
   cout<<"\t\t读取学生信息成功!"<<endl;
  }
}
  
Studentmassage::~Studentmassage()
 {
  Save();
  for(Student * temp;Head->Next!=End;)
  {
   temp=Head->Next;
   Head->Next=Head->Next->Next;
   delete temp;
  }
  delete Head,End;
 }
  
void Studentmassage::ShowMenu()                  
{
   cout<<"********************************************************************************"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓〓  ☆   学 生 成 绩 管 理 系  统     ☆  〓〓〓〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓★★★★★          ★★★★★★★        ★★★★★〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓★  ☆          A.增加学生成绩        ☆  ★〓〓〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓★  ☆          S.显示学生成绩        ☆  ★〓〓〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓★  ☆          H.排序统计成绩        ☆  ★〓〓〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓★  ☆          Q.查找学生成绩        ☆  ★〓〓〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓★  ☆          D.删除学生成绩        ☆  ★〓〓〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓★  ☆          M.修改学生信息        ☆  ★〓〓〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓★  ☆          T.统计学生信息        ☆  ★〓〓〓〓〓〓〓〓〓"<<endl;
   cout<<"〓〓〓〓〓〓〓〓〓★  ☆          E.安全退出系统        ☆  ★〓〓〓〓〓〓〓〓〓"<<endl;
   
  cout<<"\n\t\t\n\t\t请选择：";
}
  
void Studentmassage::Find()
{
  char name[20] ,Id[10];
  int x;
  Student * p=NULL;
  cout<<"\n\t\t*********************************\n";
  cout<<"\t\t※ 1.按学生的姓名查找\n\t\t※ 2.按学生学号查找";
  cout<<"\n\t\t*********************************\n请选择：";
  cin>>x;
  switch(x)
  {
  case 1:{cout<<"\t\t请输入要查找的学生的姓名：";cin>>name;
   if(p=FindItem(name))
   {
    p->Next->Show();
    cout<<"输入任意字符！继续……";
    getch();
   }
   else
   {
    cout<<"\t\t没有找到该姓名的学生！"<<'\n'<<endl;
    cout<<"输入任意字符！继续……";
    getch();
   }
      }break;
  case 2:
   {
    cout<<"\t\t请输入要查找的学生的学号：";cin>>Id;
    if(p=FindID(Id))
    {
     p->Next->Show();
     cout<<"输入任意字符！继续……";
     getch();
    }
    else
    {
     cout<<"\t\t没有找到该学好的学生！"<<'\n'<<endl;
     cout<<"输入任意字符！继续……";
     getch();
    }
   }break;
  }
   
}

void Studentmassage::t()
{
    int e=0,g1=0,g2=0,g3=0,g4=0,g5=0,n=0;
    for(Student * p=Head->Next;p!=End;p=p->Next)
    {
        n++;
        e=e+p->Cnum;
        if(p->Cnum>=90)
            g1++;
        else if(p->Cnum>=80)
            g2++;
        else if(p->Cnum>=70)
            g3++;
        else if(p->Cnum>=60)
            g4++;
    }
    cout<<"c++的平均分是："<<e/n<<endl;
    cout<<"90~100"<<ends<<g1<<endl<<"80~89"<<ends<<g2<<endl<<"70~79"<<ends<<g3<<endl<<"60~69"<<ends<<g4<<endl<<"<60"<<ends<<n-g1-g2-g3-g4<<endl;

    e=0;g1=0;g2=0;g3=0;g4=0;
    for(Student * q=Head->Next;q!=End;q=q->Next)
    {
        e=e+q->Mnum;
        if(q->Mnum>=90)
            g1++;
        else if(q->Mnum>=80)
            g2++;
        else if(q->Mnum>=70)
            g3++;
        else if(q->Mnum>=60)
            g4++;
    }
    cout<<"汇编课程的平均分是："<<e/n<<endl;
    cout<<"90~100"<<ends<<g1<<endl<<"80~89"<<ends<<g2<<endl<<"70~79"<<ends<<g3<<endl<<"60~69"<<ends<<g4<<endl<<"<60"<<ends<<n-g1-g2-g3-g4<<endl;

    e=0;g1=0;g2=0;g3=0;g4=0;
    for(Student * h=Head->Next;h!=End;h=h->Next)
    {
        e=e+h->Enum;
        if(h->Enum>=90)
            g1++;
        else if(h->Enum>=80)
            g2++;
        else if(h->Enum>=70)
            g3++;
        else if(h->Enum>=60)
            g4++;
    }
    cout<<"嵌入式操作系统的平均分是："<<e/n<<endl;
    cout<<"90~100"<<ends<<g1<<endl<<"80~89"<<ends<<g2<<endl<<"70~79"<<ends<<g3<<endl<<"60~69"<<ends<<g4<<endl<<"<60"<<ends<<n-g1-g2-g3-g4<<endl;

    e=0;g1=0;g2=0;g3=0;g4=0;
    for(Student * k=Head->Next;k!=End;k=k->Next)
    {
        e=e+k->math;
        if(k->math>=90)
            g1++;
        else if(k->math>=80)
            g2++;
        else if(k->math>=70)
            g3++;
        else if(k->math>=60)
            g4++;
    }
    cout<<"数学的平均分是："<<e/n<<endl;
    cout<<"90~100"<<ends<<g1<<endl<<"80~89"<<ends<<g2<<endl<<"70~79"<<ends<<g3<<endl<<"60~69"<<ends<<g4<<endl<<"<60"<<ends<<n-g1-g2-g3-g4<<endl;
    getch();
}



   
  
void Studentmassage::ModifyItem()     
{
  char name[20];
  Student * p=NULL;
  cout<<"\t\t请输入要修改的人的姓名:";cin>>name;
  if(p=FindItem(name))
  {
   cout<<"\t\t已找到学生的信息，请输入新的信息!"<<endl;
   p->Next->Input();
   cout<<"修改成功！"<<endl;
   cout<<"输入任意字符！继续……";
   getch();
  }
  else
  {
   cout<<"\t\t没有找到!"<<endl;
   cout<<"输入任意字符！继续……";
   getch();
  }
}
  
void Studentmassage::RemoveItem()        
{
  char name[20];
  Student * p=NULL,*temp=NULL;
  cout<<"\t\t请输入要删除的学生的姓名:"<<endl;cin>>name;
  if(p=FindItem(name))
  {
   temp=p->Next;
   p->Next=p->Next->Next;  
   delete temp;
   cout<<"\t\t删除成功!"<<endl;
   cout<<"输入任意字符！继续……";
   getch();
  }
  else
  {
   cout<<"\t\t没有找到!"<<endl;
      cout<<"输入任意字符！继续……";
   getch();
  }
}
  
void Studentmassage::Swap(Student *p1, Student *p2)
{
  Student *temp=new Student;  
  strcpy(temp->name,p1->name);
  strcpy(temp->Id,p1->Id);
  strcpy(temp->sex,p1->sex);
  temp->age=p1->age;
  temp->Cnum=p1->Cnum;
  temp->Mnum=p1->Mnum;
  temp->Enum=p1->Enum;
  temp->math=p1->math;
  temp->sum=p1->sum;
  temp->average=p1->average;
   
  strcpy(p1->name,p2->name);
  strcpy(p1->Id,p2->Id);
  strcpy(p1->sex,p2->sex);
  p1->age=p2->age;
  p1->Cnum=p2->Cnum;
  p1->Mnum=p2->Mnum;
  p1->Enum=p2->Enum;
  p1->math=p2->math;
  p1->sum=p2->sum;
  p1->average=p2->average;
   
  strcpy(p2->name,temp->name);
  strcpy(p2->Id,temp->Id);
  strcpy(p2->sex,temp->sex);
  p2->age=temp->age;
  p2->Cnum=temp->Cnum;
  p2->Mnum=temp->Mnum;
  p2->Enum=temp->Enum;
  p2->math=temp->math;
  p2->sum=temp->sum;
  p2->average=temp->average;
}
  
int Studentmassage::ListCount()
{
  if(! Head)
   return 0;
  int n=0;
  for(Student * p=Head->Next;p!=End;p=p->Next)
  {
   n++;
  }
  return n;
}
  
void Studentmassage::Sort()
{  
  cout <<"Sorting..."<<endl;
  Student *p=NULL,*p1=NULL,*k=NULL;
  int n=Studentmassage::ListCount();
  if(n<2)  
   return;
  for(p=Head->Next;p!=End;p=p->Next)
   for(k=p->Next;k!=End;k=k->Next)
   {
    if(p->sum>k->sum)
    {
     Studentmassage::Swap(p,k);
    }
   }
  cout <<"排序完成！"<<endl;
  getch();
  return;
}
  
void Studentmassage::Save()
{
  out.open("sort.txt");
  for(Student *p=Head->Next;p!=End;p=p->Next)
   out<<p->name<<"\t"<<p->Id<<"\t"<<p->Cnum<<"\t"
   <<p->Mnum<<"\t"<<p->Enum<<"\t"<<p->sum<<'\n';
  out.close();
}
  
int main()
{
    system("color f5");
  int i=0;
  char x;
  bool quit=false;
  cout<<"\t\t§§§§§§§§§§§§§§§§§§§§§§§§§§"<<endl;
  for(i=0;i<3;i++)
   cout<<"\t\t◎\t\t\t\t\t\t  ◎"<<endl;
  cout<<"\t\t◎★★★★【  欢迎进入学生成绩管理系统  】★★★★◎"<<endl;
  for(i=0;i<3;i++)
   cout<<"\t\t◎\t\t\t\t\t\t  ◎"<<endl;
  cout<<"\t\t§§§§§§§§§§§§§§§§§§§§§§§§§§\n"<<endl;;
  Studentmassage Grade;
  cout<<"按任意键开始……";
   getch();
  while(!quit)
  {
   system("cls");
   Grade.ShowMenu();
   cin>>x;
   switch(x)
   {
   case 'E':quit=true;break;
   case 'A':Grade.AddItem();break;
   case 'S':Grade.Display();break;
   case 'H':Grade.Sort();break;
   case 'Q':Grade.Find();break;
   case 'D':Grade.RemoveItem();break;
   case 'T':Grade.t();break;
   case 'M':Grade.ModifyItem();break;
   }
  }
  return 0;
}

cin cout什么的都换成 scanf printf 什么的，话说VC都能用，为啥要换成C呢

因为我们交的作业要是C语言格式的TT

class Studentmassage这是一个类，C语言中可没有类的

這個本來就是C程序。不是戴了頂C++的帽子，就是C++程序的。

这个和C有毛的区别，不要说用cout、cin在定义两个类就是面向对象编程。

我尝试改了下，但是感觉好慢呀，对C++不熟悉

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "student_system.h"
int main(void) 
{ 
    system("color f5");
    int i=0; 
    char x;
    bool quit=false; 
    printf("§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§\n"); 

    printf("\t\t◎★★★★【  欢迎进入学生成绩管理系统  】★★★★◎\n"); 

    printf("§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§§\n"); 
    printf("按任意键开始……"); 
    getchar();
    load_mima();
    while(!quit) 
    { 
        system("cls");
        Studentmassage_ShowMenu();
        fflush(stdin);
        scanf("%c",&x);
        getchar();
        switch(x) 
        { 
        case 'E':quit=true;break;  
        case 'A':AddItem();break; 
        case 'S':Display();break; 
        case 'H':Sort();break; 
        case 'Q':Find();break; 
        case 'D':RemoveItem();break; 
        case 'T':t();break;
        case 'M':ModifyItem();break; 
        default:
            {
                printf("Is wrong");
                break;
            }
        } 
    } 
    return 0; 
}

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include "student_system.h"
void build_new()
{
    mima *passbook1;
    passbook1=(mima*)malloc(sizeof(mima));
    size_t length1,length2;
    FILE *fp_1;
    printf("请输入新的用户名和密码\n");
    printf("用户名：");
    /*gets(passbook1->user_name);*/
    scanf("%s",passbook1->user_name);
    getchar();
    printf("密码：");
    scanf("%s",passbook1->password);
    getchar();
    /*gets(passbook1->password);*/
    fp_1=fopen("load_pass.txt","wb");
    length1=strlen(passbook1->user_name);
    length2=strlen(passbook1->password);
    if(fwrite(&length1,sizeof(length1),1,fp_1)!=1)
        printf("写入文件错误!\n");
    else
    {
        /*printf("写入文件成功1!\n");
        printf("length1=%d!\n",length1);*/
        fflush(stdin);
        fwrite(passbook1->user_name,sizeof(char),length1,fp_1);
        /*for(int i=0;i<length1;i++)
            printf("输入的账号是%c\n",passbook1->user_name[i]);*/
    }
    if(fwrite(&length2,sizeof(length2),1,fp_1)!=1)        
        printf("写入文件错误!\n");
    else
    {
        /*printf("写入文件成功2!\n");
        printf("length2=%d!\n",length2);*/
        fflush(stdin);
        fwrite(passbook1->password,sizeof(char),length2,fp_1);
        /*for(int i=0;i<length2;i++)
            printf("输入的密码是%c\n",passbook1->password[i]);*/
    }
    fclose(fp_1);    

}

int load_user()
{
    mima   *passbook1,*passbook2;
    passbook2=(mima*)malloc(sizeof(mima));
    passbook1=(mima*)malloc(sizeof(mima));
    size_t length1,length2;
    FILE *fp_2;
    printf("请输入用户名和密码\n");
    printf("用户名：");
    gets(passbook1->user_name);
    printf("密码：");
    gets(passbook1->password);
    if((fp_2=fopen("load_pass.txt","rb"))!=NULL)
    {

        if(fread(&length1,sizeof(length1),1,fp_2)!=1)        
            printf("读入文件错误!\n");
        else
        {
            fread(passbook2->user_name,sizeof(char),length1,fp_2);
            passbook2->user_name[length1]='\0';
            /*printf("已经得到用户名\n");*/
            /*for(int i=0;i<length1;i++)
                printf("已经得到用户名是%c\n",passbook2->user_name[i]);*/
            fflush(stdout);
        }
        if(fread(&length2,sizeof(length2),1,fp_2)!=1)        
            printf("读入文件错误!\n");
        else
        {
            fread(passbook2->password,sizeof(char),length2,fp_2);
            passbook2->password[length2]='\0';
            /*printf("已经得到密码\n");
            for(int i=0;i<length2;i++)
                printf("已经得到密码是%c\n",passbook2->password[i]);*/
            fflush(stdout);
        }
    }

    if((!strcmp(passbook2->user_name,passbook1->user_name))&&(!strcmp(passbook2->password,passbook1->password)))
    {
            free(passbook2);
            free(passbook1);
            printf("恭喜你登录成功！\n");
            system("pause");
            fclose(fp_2);
            return 1;
    }
    else
    {
        free(passbook2);
        free(passbook1);
        printf("非常抱歉，失败了！\n");
        fclose(fp_2);
        return 0;
    }
}

int load_mima()
{  
    char c;
    bool quit=false;
    printf("你是新用户？Y or N\n");
    scanf("%c",&c);
    getchar();
    while(1)
    {
      switch(c)
        {
          case 'y':
          case 'Y':build_new();
          case 'n':
          case 'N':
              while(!quit)
                  {
                      if(load_user()==1)
                          quit=true;
                      else
                          printf("错误，请重新输入!\n");
                   }
                return 0;
          default:printf("错误，请重新输入!\n");
                  continue;
        }
    } 
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "student_system.h"
#define N 100
struct Student stu[N]={0};
struct Student *s=stu;

void Studentmassage_ShowMenu()                   
{ 
    printf("********************************************************************************"); 
    printf("〓〓〓〓〓〓〓〓〓〓  ☆   学 生 成 绩 管 理 系  统     ☆  〓〓〓〓〓〓〓〓〓〓"); 
    printf("〓〓〓〓〓〓〓★★★★★          ★★★★★★★        ★★★★★〓〓〓〓〓〓〓"); 
    printf("〓〓〓〓〓〓〓〓〓★  ☆          A.增加学生成绩        ☆  ★〓〓〓〓〓〓〓〓〓"); 
    printf("〓〓〓〓〓〓〓〓〓★  ☆          S.显示学生成绩        ☆  ★〓〓〓〓〓〓〓〓〓"); 
    printf("〓〓〓〓〓〓〓〓〓★  ☆          H.排序统计成绩        ☆  ★〓〓〓〓〓〓〓〓〓"); 
    printf("〓〓〓〓〓〓〓〓〓★  ☆          Q.查找学生成绩        ☆  ★〓〓〓〓〓〓〓〓〓"); 
    printf("〓〓〓〓〓〓〓〓〓★  ☆          D.删除学生成绩        ☆  ★〓〓〓〓〓〓〓〓〓"); 
    printf("〓〓〓〓〓〓〓〓〓★  ☆          M.修改学生信息        ☆  ★〓〓〓〓〓〓〓〓〓");
    printf("〓〓〓〓〓〓〓〓〓★  ☆          T.统计学生信息        ☆  ★〓〓〓〓〓〓〓〓〓");
    printf("〓〓〓〓〓〓〓〓〓★  ☆          E.安全退出系统        ☆  ★〓〓〓〓〓〓〓〓〓");     
    printf("\n\t\t\n\t\t请选择："); 
} 
void Input(Student *s) 
{ 
    printf("\t\t请输入学生的姓名："); 
    scanf("%s",s->name);
    printf("\t\t请输入学生的学号："); 
    scanf("%s",s->Id);
    printf("\t\t请输入学生的性别：");
    scanf("%s",s->sex);
    printf("\t\t请输入学生的年龄：");
    scanf("%d",&s->age);
    printf("\t\t请输入C++课程的成绩：");
    scanf("%d",&s->Cnum);
    printf("\t\t请输入汇编课程的成绩："); 
    scanf("%d",&s->Mnum);
    printf("\t\t请输入嵌入式操作系统课程的成绩：");
    scanf("%d",&s->Enum);
    getchar();
    printf("\t\t请输入数学成绩：");
    scanf("%d",&s->math);
    s->sum=s->Cnum+s->Mnum+s->Enum+s->math; 
    printf("\t\t总成绩=%d",s->sum);
    s->average=s->sum/4;
    printf("\t\t平均成绩=%d",s->average);
  } 
void AddItem() 
{ 
    /*struct Student *sS=new Student();*/

    char pan;
    while(1)
    {
      Input(s);
      s++;
      while(1)
      {   
          printf("\n");
          getchar();
          printf("是否继续输入？（Y/N）");
          scanf("%c",&pan);
         
          switch(pan)
          {
          case 'N':
          case 'n':
              return;
          case 'Y':
          case 'y':
              break;
          default:
              printf("错误，请重新输入!\n");
              continue;
          }
          break;
      }
    }
}

    

void Display()
{
    struct Student *p=stu;
    while(p->name[0]!=NULL)
    {
    printf("--------------------------------------------------------------------\n");    
    printf("%6s%6s%6s%6s%6s%6s%6s%6s%6s%6s\n","姓名","学号","性别","年龄","成绩1","成绩2","成绩3","成绩4","平均成绩","总成绩");
    printf("--------------------------------------------------------------------\n"); 
    printf("%6s%6s%6s%6d%6d%6d%6d%6d%6d%6d",p->name,p->Id,p->sex,p->age,p->Cnum,p->Enum,p->Mnum,p->math,p->average,p->sum);
    printf("\n--------------------------------------------------------------------\n"); 
    p++;
    }
    printf("\n\n");
    system("pause");
}
void Sort()
{
}
void Find()
{
}
void RemoveItem()
{
}
void t()
{
}
void ModifyItem()
{
}

  

#ifndef STUDENT_SYSTEM_H
#define STUDENT_SYSTEM_H
void Studentmassage_ShowMenu();
void AddItem();
void Display();
void Sort();
void Find();
void RemoveItem();
void t();
void ModifyItem();
struct  Student 
{ 
    char name[20]; 
    char Id[20];
    char sex[4];
    int age;
    int Cnum;       
    int Mnum;       
    int Enum;       
    int math;
    int sum;        
    int average;
    Student * Next; 
};
typedef struct load
{
    char user_name[50];
    char password[50];
}mima;
void build_new();
int load_user();
int load_mima();
#endif