#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct st
{
    char name[20];
    int english;
    int math;
    int chinese;
    int average;
    st *next;
    
};
struct st *pend=NULL;//初始鏈表的尾指針 
struct st *pendorder=NULL;//順序鏈表的尾指針 
struct st *pheadorder=NULL;//順序鏈表的頭指針 
struct st *makeorder(struct st *phead);//按分數(shù)從大到小排序 生產(chǎn)鏈表 
struct st *addtolist(struct st *add);// 將平均分最大的添到另一個鏈表 
struct st *createlist();//輸入學(xué)生信息時生成的初始鏈表 
struct st * deletestu(char *name,st *phead);//刪除一個學(xué)員的信息 
struct st *addstu(st *name,st *phead);//向順序鏈表添加一個元素，插入的地方按平均成績 
void printinfo(st *phead);//按平均成績打印出每個學(xué)員的名字 
int main()
{
  int select;
  char deletename[20];
  struct st *addstud=NULL;
  struct st *phead=NULL; 
  phead=createlist();//輸入時創(chuàng)建鏈表 
  pheadorder=makeorder(phead);//將鏈表排序 
  printf("input operation:1----deletestudent,2-----addstudent,3----output all student\n");
  scanf("%d",&select);
  while(select>0)//選擇操作1為刪除2為添加3為打印，其他的輸入會跳出循環(huán) 
  {
    switch(select)
      {
              
              case 1:
                  printf("please input the of the student to be deleted:\n");
                  scanf("%s",deletename);
                  pheadorder=deletestu(deletename,pheadorder);
                  printf("input operation:1----deletestudent,2-----addstudent,3----output all student\n");
                  scanf("%d",&select);
                  break;
              case 2:
                  printf("please input the information of the student to be added:\n");
                  addstud=new st;
                  scanf("%s%d%d%d",addstud->name,&(addstud->english),&(addstud->math),&(addstud->chinese));
                  addstud->average=((addstud->english)+(addstud->math)+(addstud->chinese))/3;
                  while((addstud->english)<=0)
                  {
                  delete addstud;
                  printf("please input the information of the student to be added:\n");
                  addstud=new st;
                  scanf("%s%d%d%d",addstud->name,&(addstud->english),&(addstud->math),&(addstud->chinese));
                  addstud->average=((addstud->english)+(addstud->math)+(addstud->chinese))/3;
                  }
                  pheadorder=addstu(addstud,pheadorder);
                  printf("input operation:1----deletestudent,2-----addstudent,3----output all student\n");
                  scanf("%d",&select);
                  break;
              case 3:
                  printinfo(pheadorder);
                  printf("input operation:1----deletestudent,2-----addstudent,3----output all student\n");
                  scanf("%d",&select);
                  break;
              default:
                  goto laber;
              
      }
  }
  laber:system("pause");
  return 1;
  
}
struct st *createlist()//輸入時創(chuàng)建初始鏈表 
{
    struct st *pfirst=NULL;
    struct st *plast=NULL;
    struct st *p=new st;
    printf("please input the information of the students:\n");
    scanf("%s%d%d%d",p->name,&(p->english),&(p->math),&(p->chinese));
    p->average=((p->english)+(p->math)+(p->chinese))/3;
    while((p->english)>0)
    {
            if(pfirst==NULL)
            pfirst=plast=p;
            else
            plast->next=p;
            plast=p;
            printf("please input again:\n");
            p=new st;
            scanf("%s%d%d%d",p->name,&(p->english),&(p->math),&(p->chinese));
            p->average=((p->english)+(p->math)+(p->chinese))/3;
          
    }
    plast->next=NULL;
    printf("list create successful\n");
    delete p;
    return pfirst;
}
struct st *deletestu(char *name,st *phead)//刪除一個學(xué)員 
{
    int flag=0;
    st *p=NULL;
    if(strcmp(phead->name,name)==0)
    {
    phead=phead->next;
    flag=1;
    }
    else
    for(p=phead;p;p=p->next)
    {
    if(strcmp(p->next->name,name)==0)
      {
        p->next=p->next->next;
        flag=1;
        break;                
      }
    }
    if(!flag)
    printf("the student you delete is not in the list\n");
    else printf("delete successful\n");
    return phead;
}
struct st *addstu(st *name,st *phead)//按平均分增加一個學(xué)員 
{
    name->next=NULL;
    struct st *p=NULL;
    if((name->average)>(phead->average))
    {
      name->next=phead;
      phead=name;
      return phead;
    }
    else
    {
      for(p=phead;p->next;p=p->next)
      {
        if((name->average)>(p->next->average))
        {
          name->next=p->next;
          p->next=name;
          return phead;
        }
        
        
      }
    }
    p=p->next;
    p->next=name;
    return phead;
    
    
}
void printinfo(st *phead)//打印信息 
{
    st *p;
    for(p=phead;p;p=p->next)
    printf("%s\n",p->name);
}

struct st *addtolist(struct st *phead,struct st *add)//生成順序鏈表時每回都添加一個平均成績最高的學(xué)員信息 
{
    add->next=NULL;
    if(phead==NULL)
    pendorder=phead=add;
    else
    pendorder->next=add;
    pendorder=add;
    return phead;
    
} 

struct st *makeorder(struct st *phead)//將初始鏈表變成順序鏈表 
{
    if(phead!=NULL)
    {
    int max;
    struct st *p=NULL;
    struct st *index=NULL;
    while(phead)
    {
    max=0;
    for(p=phead;p;p=p->next)
    {
                    if(p->average>max)
                    {
                    max=p->average;
                    index=p;
                    }
    }
    phead=deletestu(index->name,phead);
    pheadorder=addtolist(pheadorder,index);
    }
    return pheadorder;
    }
    else printf("there is no list members to be ordered\n");
    return pheadorder;
}