C++学习第2天 简单的商品管理系统

//代码来自 书本

#include <iostream>#include <limits>   // 为了使用numeric_limits#include <sstream> //为了使用字符串输入输出流#include <fstream>  //为了执行文件输入输出操作using namespace std;struct goods {int type;int num;float price;};const char*file="goods.dat";class Data {public:Data(int number,float Price):num(number),price(Price){}virtual ~Data(){};int GetNumber()const{return num;}float GetPrice()const{return price;}virtual void Print()const =0;private:int num;float price;};class Book:public Data{public:Book(int number,float Price);virtual void Print()const{cout<<"图书编号为:"<<GetNumber()<<endl;cout<<"图书价格为:"<<GetPrice()<<endl;}};Book::Book(int number,float Price):Data(number,Price){}class Drug:public Data{public :Drug(int number,float Price);virtual void Print()const{cout<<"药品编号为:"<<GetNumber()<<endl;cout<<"药品价格为:"<<GetPrice()<<endl;}};Drug::Drug(int number,float Price):Data(number,Price){} class Node{public:Node(Data*);~Node();void SetNext(Node*node){itsnext=node;}Node*GetNext()const;Data*GetData()const;private:Data*itsData;Node*itsnext;};Node::Node(Data*pData):itsData(pData),itsnext(0){}Node::~Node(){delete itsData;itsData=0;}Node*Node::GetNext()const{return itsnext;}Data*Node::GetData()const{if(itsData)return itsData;elsereturn NULL;}class List{public:List();~List();Data*Find(int number)const;//重载一个带两个参数的Find()函数Data*Find(int &increase,int number)const;int GetCount()const{return count;}Data*GetFirst()const;void Insert(Data*);void Show()const;Data*operator[](int)const;void Delete(int num);private:Node*head;int count;};List::List():head(0),count(0){}List::~List(){Node*l=head;Node*m=0;int n=0;while(l){m=l;l=l->GetNext();n++;cout<<"程序结束，删除第"<<n<<"个节点\n";delete m;}}Data*List::GetFirst()const{if (head)return head->GetData();elsereturn NULL;}Data*List::operator[](int offset)const{Node*pn=head;if(!head)return NULL;if(offset>=count)return NULL;for(int i=0;i<offset;i++)pn=pn->GetNext();return pn->GetData();}Data*List::Find(int number)const{Node*pn=0;for(pn=head;pn!=NULL;pn=pn->GetNext()){if(pn->GetData()->GetNumber()==number)break;}if(pn==NULL)return NULL;elsereturn pn->GetData();}//重载一个带两个参数的Find()函数Data*List::Find(int &increase,int number)const{Node*pn=0;for(pn=head,increase=0;pn!=NULL;pn=pn->GetNext(),increase++){if(pn->GetData()->GetNumber()==number)break;}if(pn==NULL)return NULL;elsereturn pn->GetData();} void List::Show()const{if(!head)return;Node*pn=head;do pn->GetData()->Print();while(pn=pn->GetNext());}void List::Delete(int num){Node*pBack=head;Node*pNow=head;if(!head){cout<<"没有数据可删除！\n";return;}if(head->GetData()->GetNumber()==num){if (!head->GetNext()){delete head;cout<<"数据被清空！\n";head=0;count--;return;}else{head=head->GetNext();delete pNow;pNow=0;cout<<"删除成功！\n";count--;return;}}while(pBack){if (pBack->GetNext()==NULL){cout<<"找不到要删除的编号。";return;}if(pBack->GetNext()->GetData()->GetNumber()==num){pNow=pBack->GetNext();pBack->SetNext(pNow->GetNext());delete pNow;cout<<"删除数据成功！\n";count--;return;}pBack=pBack->GetNext();}cout<<"不存在此编号！\n";}void List::Insert(Data*pData){Node*pn=new Node(pData);Node*pNow=head;Node*pNext=0;int New=pData->GetNumber();int next=0;count++;if(!head){head=pn;return;}if(head->GetData()->GetNumber()>New){pn->SetNext(head);head=pn;return;}for(;;){if(!pNow->GetNext()){pNow->SetNext(pn);return;}pNext=pNow->GetNext();next=pNext->GetData()->GetNumber();if(next>New){pNow->SetNext(pn);pn->SetNext(pNext);return;}pNow=pNext;}}class Repair:private List{public:void RInsert(Data*);void Run();private:};void Repair::RInsert(Data*newData){int num=newData->GetNumber();int place=0;if(!Find(place,num))Insert(newData);else{cout<<"您输入的编号"<<num<<"与链表中";cout<<"第"<<place+1<<"个编号重复\n";}}  void Repair::Run(){//List pl;Data*pData=0;int number;float price;int choice;bool quit=false;bool load=false;bool save=false;while (1){system("cls");cout<<"(1)增加商品(2)列出所有商品(3)删除商品(4)查找商品(5)商品数目(6)退出(7)读取(8)保存:";cin>>choice;switch (choice){case 1:while (1){cout<<"(0)返回(1)图书(2)药品:";cin>>choice;if (!choice){break;}else if (choice==1||choice==2){cout<<"请输入编号:";cin>>number;if (choice==1){cout<<"请输入图书价格:";cin>>price;pData=new Book(number,price);RInsert(pData);}else if (choice==2){cout<<"请输入药品价格:";cin>>price;pData=new Drug(number,price);RInsert(pData);}}elsecout<<"请输入0-2之间的数字\n";}break;case 2:if(GetFirst()==0){cout<<"您的商品为空，请增加商品，\n"<<"按回车键返回主窗口"<<endl;cin.get();cin.get();}else{Show();cout<<"请按回车键返回主窗口"<<endl;cin.get();cin.get();}break;case 3:cout<<"请输入您要删除的商品编号："<<endl;cin>>number;Delete(number);cin.get();cin.get();break;case 4:while (1){cout<<"(0)返回(1)按编号进行查询(2)按序号进行查询:";cin>>choice;if(!choice){break;}if(choice==1){cout<<"请输入所要查找的商品的编号："<<endl;cin>>number;Data*result=Find(number);if(result==0)cout<<"找不到该编号。\n";elseresult->Print();}else if(choice==2){cout<<"请输入所要查找的数据的序号："<<endl;cin>>number;if ((*this)[number-1]){(*this)[number-1]->Print();}elsecout<<"找不到您要查询的数据。\n";}elsecout<<"请输入0-2之间的数字\n";}break;case 5:cout<<"该链表共有"<<GetCount()<<"节点\n";cin.get();cin.get();break;case 6:quit=true;break;case 7:{fstream In; int num=0;In.open(file,ios::in|ios::out|ios::binary);if (In.is_open()){In.seekp(0);string ch;In>>ch;stringstream ssout;ssout<<ch;ssout>>num;cout<<"当前内容为："<<file<<"\n";if (num==0){cout<<"文件读取成功。\n";cout<<"您的商品为空，请增加商品，\n"<<"按回车键返回主窗口"<<endl;cin.get();cin.get();break;}cout<<"读入"<<num<<"个商品记录。"<<endl;In.ignore();goods pp={0};while (In.read((char*)&pp,sizeof pp)){if (pp.type==1){pData=new Book(pp.num,pp.price);RInsert(pData);}else if (pp.type==2){pData=new Drug(pp.num,pp.price);RInsert(pData);}elsecontinue;}if (In.eof()){In.clear();}else{cerr<<"读取错误"<<file<<".\n";exit(EXIT_FAILURE);}}else{cerr<<file<<"不能打开\n";exit(EXIT_FAILURE);}Show();cout<<"读取成功\n";cin.get();cin.get();In.close();}break;case 8:{int num=GetCount();goods *pp=new goods[num];ofstream fout(file,ios::out|ios::binary);fout<<num<<" ";for (int i=0;i<num;i++){Data*p=(*this)[i];if (p){if ((typeid(*p).name())==(typeid(Book).name())){pp->type=1;cout<<"存入商品类型:图书"<<"\t";}else if((typeid(*p).name())==(typeid(Drug)).name()){pp->type=2;cout<<"存入商品类型:药品"<<"\t";}else{pp->type=0;cout<<"存入商品类型:无"<<"\t";}pp->num=p->GetNumber();cout<<"编号："<<pp->num<<"\t";pp->price=p->GetPrice();cout<<"价格："<<pp->price<<endl;fout.write((char*)&(*pp),sizeof (*pp));}else{break;}pp++;}cout<<"保存成功\n";cin.get();cin.get();fout.close();}break;default:cin.clear();//清除cin流的错误状态 cin.ignore( numeric_limits<streamsize>::max(), '\n' );cout<<"您只可以输入1-6之间的数字,请重新输入"<<endl<<"请按回车键返回并重新录入"<<endl; cin.get();break;}if (quit){cout<<"程序结束\n";break;}}}int main(){Repair rp;rp.Run();return 0;}