【C++】单链表实现学生成绩表系统

#include<iostream>
#include<string.h>
#include <fstream>
#include"stdlib.h"
using namespace std;
class Node{
public:
int num;
char name[20];
float Math;
float English;
float Physics;
float average;
Node *next;
};
class StudList
{
private:
Node *head;                                                    //头节点
public:
StudList();
void CreateList();                                                 //创建链表
void Display();                                                    //显示链表
int getlen() ;                                               //获取链表长度
//  bool isEmpty();                                              //判断链表是否为空
//  bool Find(const int n);                                      //在链表中查找某个值
//  Node* GetNode(int i);                                        //返回第i个节点
Node *GetHead();

void averGrade(Node *node);								//求平均成绩
void pushBack();                             	         //尾部添加一个学生
void Insert();                        		     //在第i个位置插入一个学生
int Delete();                               	  //删除一个个学生
int Modif();   		                        	 //修改一个个学生 的信息
void sort();								   	 //根据输入的参数决定使用某门课程成绩排序
void sortM();
void sortE();
void sortP();
void sortAver();								//平均成绩排序

void CountNot();								//查询某一门学科不及格的人数和成绩单
int CountNotM();
int CountNotE();
int C
4000
ountNotP();
};

void menu(StudList *list);
void Save(StudList *list);
void Read(StudList *list);

int main(){

StudList list;
list.CreateList();
menu(&list);
return 0;
}

StudList::StudList()
{
head=new Node();
head->next=NULL;
}

void StudList::Display(){
Node *cur=head;
int len = getlen();
cout<<"len:"<<len<<endl;
while(len--){
cout<<"  学号："<<cur->num;
cout<<"  姓名："<<cur->name;
cout<<"  Math："<<cur->Math;
cout<<"  English："<<cur->English;
cout<<"  Physics："<<cur->Physics;
cout<<"  平均成绩："<<cur->average<<endl;
cur=cur->next;
}
}

//建立一个空表
void StudList::CreateList()
{
head->num=0;
}

Node *StudList::GetHead(){
return head;
}

void StudList::pushBack(){
Node *cur,*p,*t;
if(!head){
head = new Node();
}
cur=head;
p=new Node();
t= head;

while(cur->next){
cur=cur->next;
}
cout<<"输入学号："<<endl;
cin>>p->num;
while(t){
if(t->num==p->num){
cout<<"已存在该学号！"<<endl;
return;
}
t=t->next;
}
cout<<"输入姓名："<<endl;
cin>>p->name;
cout<<"输入高数成绩："<<endl;
cin>>p->Math;
cout<<"输入英语成绩："<<endl;
cin>>p->English;
cout<<"输入物理成绩："<<endl;
cin>>p->Physics;
averGrade(p);
if(head->num==0){
head = p;
return;
}
cur->next = p;
p->next=NULL;
}

void StudList::averGrade(Node *node){
node->average = (node->English+node->Math+node->Physics)/3;
}

//获取单链表长度
int StudList::getlen(){
int n=0;
Node *cur;
cur=head;
while( cur ){
n++;
cur=cur->next;
}
return n;
}

//插入一个节点
void StudList::Insert(){
int i,len;
cout<<"输入要插入学生的位置(不能插入到第一个学生前和超过最后一个学生之后，即n>1，n<=len)：";
cin>>i;
len=getlen();
if(i<=2||i>len){

}
Node *cur,*t,*pr,*newNode;
if(head==NULL||head->num==0){
cout<<"当前表为空！"<<endl;
StudList();
return;
}
cur=head;
pr = head;
i-=1;		//这里的i根据情况来定，如果i表示的下标则不需要，表示位数则需要对i-1;
while(cur&&i--){
pr=cur;
cur=cur->next;
}
newNode = new Node();
t=head;
cout<<"输入插入学生的学号："<<endl;
cin>>newNode->num;
while(t){					//判断是否从在已有学号
if(t->num==newNode->num){
cout<<"已存在该学号!"<<endl;
return;
}
t=t->next;
}
cout<<"输入姓名："<<endl;
cin>> newNode->name;
cout<<"输入高数成绩："<<endl;
cin>>newNode->Math;
cout<<"输入英语成绩："<<endl;
cin>>newNode->English;
cout<<"输入物理成绩："<<endl;
cin>>newNode->Physics;
averGrade(newNode);

pr->next=newNode;
newNode->next=cur;

}

//删除
int StudList::Delete() {				//n表示学号
int n;
Node *cur,*pr;
cur=head;
pr=head;
cout<<"输入要删除学生的学号：";
cin>>n;
while(cur){
if(cur->num==n){
if(cur==head){			//如果删除的是头节点，直接令头节点为头节点的下一节点
head=head->next;
return 1;
}
pr->next=cur->next;
return 1; 					//若删除的是最后一个节点则不能使用 cur->next->next,前边已经 cur = cur->next;不许操作
}
pr=cur;
cur=cur->next;
}
cout<<"没有查到要删除的学号"<<endl;
return -1;
}

//修改指定学号学生的信息
int StudList::Modif(){			//n为学号
int a,n;
Node *cur;
cur=head;
cout<<"输入要修改学生的学号：";
cin>>n;
while(cur){
if(cur->num==n){
cout<<"1.修改姓名"<<endl;
cout<<"2.修改数学成绩"<<endl;
cout<<"3.修改英语成绩"<<endl;
cout<<"4.修改物理成绩"<<endl;
cout<<"请输入要修改的项目(输入其它不做修改)：";
cin>>a ;
switch(a){
case 1:
cout<<"请输入修改姓名：";
cin>>cur->name;
return 1;
case 2:
cout<<"请输入修改的数学成绩：";
cin>>cur->Math;
return 1;
case 3:
cout<<"请输入修改的英语成绩：";
cin>>cur->English;
return 1;
case 4:
cout <<"请输入修改的物理成绩：";
cin>>cur->Physics;
return 1;
default:
cout<<"退出修改"<<endl;
return 1;
}
}
cur=cur->next;
}
return -1;
}

void swapNode(Node *a,Node *b){			//交换两节点的信息
int temp;
char c;
float ft;

temp=a->num;
a->num=b->num;
b->num=temp;

//姓名交换
for(int i=0;i<20;i++){
c=a->name[i];
a->name[i]=b->name[i];
b->name[i]=c;
}

ft=a->Math;
a->Math=b->Math;
b->Math=ft;

ft=a->English;
a->English=b->English;
b->English=ft;

ft=a->Physics;
a->Physics=b->Physics;
b->Physics=ft;

ft=a->average;
a->average=b->average;
b->average=ft;
}

void StudList::sortM(){			//按数学成绩排序
int len,inlen;
Node *cur;
len =getlen();
while(--len){
inlen = len;
cur = head;
while(inlen--){
if(cur->Math<cur->next->Math){
swapNode(cur,cur->next);
}
cur=cur->next;
}
}
}

void StudList::sortE(){			//按英语成绩排序
int len,inlen;
Node *cur;
cur=head;
len =getlen();
while(--len){
inlen = len;
cur = head;
while(cur&&inlen--){
if(cur->English<cur->next->English){
swapNode(cur,cur->next);
}
cur=cur->next;
}
}
}

void StudList::sortP(){				//按物理成绩排序
int len,inlen;
Node *cur;
cur=head;
len =getlen();
while(--len){
inlen = len;
cur = head;
while(cur&&inlen--){
if(cur->Physics<cur->next->Physics){
swapNode(cur,cur->next);
}
cur=cur->next;
}
}
}

void StudList::sortAver(){
int len,inlen,rank=1;
Node *cur;
cur=head;
len =getlen();
while(--len){
inlen = len;
cur = head;
while(cur&&inlen--){
if(cur->average<cur->next->average){
swapNode(cur,cur->next);
}
cur=cur->next;
}
}
cur=head;
while(cur){
cout<<"学号："<<cur->num<<" 姓名："<<cur->name<<"  数学成绩："<<cur->Math<<"  英语成绩："<<cur->English
<<"  物理成绩："<<cur->Physics<<"  平均成绩："<<cur->average<<" 名次："<<rank<<endl;
if(cur->next&&cur->average==cur->next->average){
cur=cur->next;
continue;
}
rank++;
cur=cur->next;
}
}

//按成绩排序
void StudList::sort(){
int m;
cout<<"1.按数学成绩排序。"<<endl;
cout<<"2.按英语成绩排序。"<<endl;
cout<<"3.按物理成绩排序。"<<endl;
cout<<" 选择某一门排序方式：";
cin>>m;
switch(m){
case 1:
sortM();
break;
case 2:
sortE();
break;
case 3:
sortP();
break;
default :
break;
}
}

int StudList::CountNotM(){
int n=0;
Node *cur;
cur = head;
while(cur){
if(cur->Math<60){
cout<<"学号："<<cur->num<<" 姓名："<<cur->name<<" 成绩："<<cur->Math<<endl;
n++;
}
cur=cur->next;
}
cout<<"共计数学不及格人数："<<n<<endl;
return n;
}

int StudList::CountNotE(){
int n=0;
Node *cur;
cur = head;
while(cur){
if(cur->English<60){
cout<<"学号："<<cur->num<<" 姓名："<<cur->name<<" 成绩："<<cur->English<<endl;
n++;
}
cur=cur->next;
}
cout<<"共计英语不及格人数："<<n<<endl;
return n;
}

int StudList::CountNotP(){
int n=0;
Node *cur;
cur = head;
while(cur){
if(cur->Physics<60){
cout<<"学号："<<cur->num<<" 姓名："<<cur->name<<" 成绩："<<cur->Physics<<endl;
n++;
}
cur=cur->next;
}
cout<<"共计物理不及格人数："<<n<<endl;
return n;
}

//统计不及格成绩名单
void StudList::CountNot(){
int m;
cout<<"1.统计数学成绩不及格名单。"<<endl;
cout<<"2.统计英语成绩不及格名单。"<<endl;
cout<<"3.统计物理成绩不及格名单。"<<endl;
cout<<"输入选择方式：";
cin>>m;
switch(m){
case 1:
CountNotM();
break;
case 2:
CountNotE();
break;
case 3:
CountNotP();
break;
default :
break;
}
}

//菜单
void menu(StudList *list){
int a;
cout<<"************************************"<<endl;
cout<<"**   欢迎使用学生成绩表管理系统   **"<<endl;
cout<<"************************************"<<endl;
while(1){

system("pause");
system("cls");
cout<<"********************************"<<endl;
cout<<"*  1.添加一个学生成绩。        *"<<endl;
cout<<"*  2.删除一个学生成绩。        *"<<endl;
cout<<"*  3.修改一个学生成绩。        *"<<endl;
cout<<"*  4.插入一个学生成绩。        *"<<endl;
cout<<"*  5.显示学生成绩表。          *"<<endl;
cout<<"*  6.按某一课成绩排序。        *"<<endl;
cout<<"*  7.统计某一课成绩不及格人数。*"<<endl;
cout<<"*  8.平均成绩排名。            *"<<endl;
cout<<"*  9.打开本地成绩表。          *"<<endl;
cout<<"*  10.按其它键退出并保存。     *"<<endl;
cout<<"********************************"<<endl;
cin>>a;
switch(a){
case 1:
list->pushBack();
break;

case 2:
list->Display();
list->Delete();
list->Display();
break;

case 3:
list->Display();
list->Modif();
list->Display();
break;

case 4:
list->Display();
list->Insert();
list->Display();
break;
case 5:
list->Display();
break;

case 6:
list->sort();
list->Display();
break;

case 7:
list->CountNot();
break;

case 8:
list->sortAver();
break;

case 9:
Read(list);
break;

default:
Save(list);
return;

}
}
}

//保存文件
void Save(StudList *list)
{
Node *p;
ofstream outfile;
p=list->GetHead();

outfile.open("Stud_data.dat",ios::binary);
if(!outfile){
cerr<<"open error!"<<endl;
return;
}
while(p){
outfile.write((char *)p,sizeof(Node));
p=p->next;
}
outfile.close();
cout<<"保存成功！"<<endl;
}

//读文件
void Read(StudList *list)
{
Node *p,*q,*h;
ifstream infile;
list->CreateList();
p=list->GetHead();
infile.open("Stud_data.dat",ios::binary);
if(!infile)
{
cerr<<"open error!"<<endl;
return;
}
while(!infile.eof()){
infile.read((char *)p,sizeof(Node));
q= new Node();
p->next = q;
p=q;
}
h=list->GetHead();
while(h->next->num){
h=h->next;
}
h->next=NULL;
infile.close();
cout<<"读取成功！"<<endl;
}