呃  楼上说的问题我改好了

如下

#include <fstream.h>
#include <iomanip.h>
#include <string.h>
#include <ctime>
#include <cstdlib>

void choose(char);
void menu();
void money(int);
int montoday(int,int,int);
int yeartoday(int,int);
int daytoday(int,int);
int inday(int,int,int);
bool choose_a(char *);

const int LENname=8;
const int LENIDc=20;
const int LENsex=4;
const int LENnat=8;
const int MAXroom=500;
const int LENphone=14;

class GuestDate{
    char name[LENname];
    char sex[LENsex];
    char IDc[LENIDc];
    char nat[LENnat];
    char phone[LENphone];
    int roomID;
    int delTag;
public:
    GuestDate() {delTag=0;}
    int year;
    int mon;
    int day;
    char *getname()            {return name;}
    char *getsex()            {return sex;}
    char *getIDc()            {return IDc;}
    char *getnat()            {return nat;}
    char *getphone()        {return phone;}
    int getdelTag()        {return delTag;}
    int  getroomID()        {return roomID;}
    void setname(char na[])     {strcpy(name,na);}
    void setsex(char na[])         {strcpy(sex,na);}
    void setIDc(char na[])         {strcpy(IDc,na);}
    void setnat(char na[])         {strcpy(nat,na);}
    void setphone(char na[])     {strcpy(phone,na);}
    void setroomID(int na)        {roomID=na;}
    void del()             {delTag=0;}
    void unDel()             {delTag=1;}
    };

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

class GuestWay{
public:
    GuestDate guest[MAXroom];
    void showdate(int);
    void showdate();
    void save();
    void open();
    void newfile();
    void del(int roomID)
    {
        guest[roomID].del();
    }
    int roomIDscan(int roomID){
        if(1==guest[roomID].getdelTag()) return 1;
        return 0;
    }
    void IDcscan(char []);

} guest ;

void GuestWay::showdate(int i)
    {    
        cout.flags(ios::left);
        cout<<setw(8)<<guest[i].getname()
                <<setw(6)<<guest[i].getsex()
                <<setw(20)<<guest[i].getIDc()
                <<setw(8)<<guest[i].getnat()
                <<setw(14)<<guest[i].getphone()
                  <<setw(6)<<guest[i].getroomID()
                  <<guest[i].year<<"."
                <<guest[i].mon<<"."
                <<setw(5)<<guest[i].day
                <<setw(3)<<inday(guest[i].year,guest[i].mon,guest[i].day)
                <<endl;
    }

void GuestWay::showdate()
    {
        cout.flags(ios::left);
            cout<<setw(8)<<"姓名"
                <<setw(6)<<"性别"
                <<setw(20)<<"身份证"
                <<setw(8)<<"籍贯"
                <<setw(14)<<"手机号"
                <<setw(6)<<"房号"
                <<setw(12)<<"入住时间"
                <<setw(3)<<"天数"
                <<endl;
        for(int i=1;i<MAXroom;i++)
            if(guest[i].getdelTag()==1)
                showdate(i);
    }

void GuestWay::save()
    {
        fstream f("GusetDate.bin",ios::out|ios::binary);
        for(int roomID=1;roomID<=MAXroom;roomID++)
            f.write((char*)&guest[roomID],sizeof(guest[roomID]));
        f.close();
    }
void GuestWay::open()
    {
    fstream f("GusetDate.bin",ios::in|ios::binary);
        int roomID=0;
        for(;;)
            {
                if(roomID>MAXroom)
                    break;
                roomID++;
                f.seekg((roomID-1)*sizeof(guest[roomID]));
                f.read((char*)&guest[roomID],sizeof(guest[roomID]));
            }
        f.close();
    }

void GuestWay::IDcscan(char IDc[])
    {
    for(int i=1;i<=MAXroom;i++)
        {
        if (0==strcmp(guest[i].getIDc(),IDc)) {
            cout.flags(ios::left);
            cout<<setw(8)<<"姓名"
                <<setw(6)<<"性别"
                <<setw(20)<<"身份证"
                <<setw(8)<<"籍贯"
                <<setw(14)<<"手机号"
                <<setw(6)<<"房号"
                <<setw(12)<<"入住时间"
                <<setw(3)<<"天数"
                <<endl;
            GuestWay::showdate(i);
            break;
        }
        else if(i==MAXroom) cout<<"没有入住该旅客"<<endl;
        }
    }

void GuestWay::newfile()
    {
        int roomID;
        char name[LENname];
        char sex[LENsex];
        char IDc[LENIDc];
        char nat[LENnat];
        char phone[LENphone];
        for(;;){time_t t=time(0);
            cout<<"输入房间"<<endl;
            cin>>roomID;
            if(0==GuestWay::roomIDscan(roomID) && roomID<MAXroom)
                guest[roomID].setroomID(roomID);
            else {
                cout<<"该房间已有人"<<endl;
                break;
            }
            cout<<"输入姓名"<<endl;
            cin>>name; guest[roomID].setname(name);
            cout<<"输入性别"<<endl;
            cin>>sex;
            guest[roomID].setsex(sex);
            cout<<"输入身份证"<<endl;
            cin>>IDc;
            guest[roomID].setIDc(IDc);
            cout<<"输入籍贯"<<endl;
            cin>>nat;
            guest[roomID].setnat(nat);
            cout<<"输入手机号"<<endl;
            cin>>phone;
            guest[roomID].setphone(phone);
            guest[roomID].year=localtime(&t)->tm_year+1900;
            guest[roomID].mon=localtime(&t)->tm_mon+1;
            guest[roomID].day=localtime(&t)->tm_mday;
            guest[roomID].unDel();
            break;
        }
        for(int i=1;i<roomID;i++){
            if(1==guest[i].getdelTag() && guest[roomID].getroomID() < guest[i].getroomID()){
                GuestDate temp;
                temp=guest[i];
                guest[i]=guest[roomID];
                guest[roomID]=temp;
            }
        }
    }

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

void menu()
{
    cout<<">>>>>按1入住"<<"  "
        <<"按2退房"<<"  "
        <<"按3显示住房信息"<<"  "
        <<"按4房间查询"<<"  "
        <<"按5身份证查询"<<"  "
        <<"按q退出<<<<<"<<"  "<<endl;
}

void choose(char key){
    switch(key){
        case 49 :
            cout<<endl;
            guest.newfile();
            break;
        case 50 :
            cout<<endl;
            cout<<"输入房间"<<endl;
            int roomID;
            cin>>roomID;
            if(0==guest.roomIDscan(roomID)) {
                cout<<"该房间没有人"<<endl;
                break;
            }
            else {
                money(inday(guest.guest[roomID].year,guest.guest[roomID].mon,guest.guest[roomID].day));
                cout<<"确定支付? 1.确定 2.返回"<<endl;
                char c[10];
                cin>>c;
                if (choose_a(c))
                    switch(c[0])
                    {
                        case 49 : cout<<"选择支付"<<endl; guest.del(roomID); break;
                        case 50 : cout<<"选择返回"<<endl; break;
                        default : cout<<"输入错误,重新输入"<<endl; break;
                    }
                else cout<<"输入错误,重新输入"<<endl;
            }
            break;
        case 51 :
            cout<<endl;
            guest.showdate();
            break;
        case 52 :
            cout<<endl;
            cout<<"输入房间"<<endl;
            cin>>roomID;
            if(0==guest.roomIDscan(roomID)) {
                cout<<"该房间没有人"<<endl;
                break;
            }
            else    {
                cout.flags(ios::left);
            cout<<setw(8)<<"姓名"
                <<setw(6)<<"性别"
                <<setw(20)<<"身份证"
                <<setw(8)<<"籍贯"
                <<setw(14)<<"手机号"
                <<setw(6)<<"房号"
                <<setw(12)<<"入住时间"
                <<setw(3)<<"天数"
                <<endl;
                guest.showdate(roomID);
                break;
                }
        case 53 :
            cout<<endl;
            char IDc[18];
            cout<<"输入身份证"<<endl;
            cin>>IDc;
            guest.IDcscan(IDc);
            break;
        case 113:
            guest.save();
            exit(0);
        default : cout<<"输入错误,重新输入"<<endl;
    }
}

bool choose_a(char *p){
int k=0;
while(*p) {p++;k++;}
if (k==1) return true;
else return false;
}


int montoday(int year,int mon,int tempmon){
    int n=tempmon-mon;
    int day=0;
    for(int i=0;i<n;i++,mon++){
    switch(mon){
        case 1 :
        case 3 :
        case 5 :
        case 7 :
        case 8 :
        case 10:
        case 12:
            day+=31;break;
        case 4 :
        case 6 :
        case 9 :
        case 11:
            day+=30;break;
        case 2 :
            if( year % 4 == 0 && year % 100 != 0 || year % 400 == 0)
                day+=29;
            else
                day+=28;
        }
    }
    return day;
}

int yeartoday(int year,int tempyear)
{
int n=tempyear-year;
int day=0;
for (int i=0;i<n;i++,year++)
    {
    if(year % 4 == 0 && year % 100 != 0 || year % 400 == 0) day+=366;
    else day+=365;
    }
    return day;
}

int daytoday(int day,int tempday)
{
if(day>tempday) {return day-tempday;}
else if(tempday>day) {return tempday-day;}
else return 0 ;
}

int inday(int year,int mon,int day)
{
int tempyear,tempmon,tempday;
time_t t=time(0);
tempyear=localtime(&t)->tm_year+1900;
tempmon=localtime(&t)->tm_mon+1;
tempday=localtime(&t)->tm_mday;
int py=yeartoday(year,tempyear);
int pm=montoday(year,mon,tempmon);
int pd=daytoday(day,tempday);
return (py+pm+pd)>1?(py+pm+pd):1 ; //不足一天算一天
}

void money(int p)
{        
    cout<<"应付:"<<p*120<<endl;  //120一天
}

void main()
{    guest.open();
    menu();
    while(1)
    {
        char key[10];
        cin>>key;
        if (choose_a(key))        
            {
            choose(key[0]);
            cout<<endl;
            menu();
            }
        else {cout<<"输入错误"<<endl<<endl;menu();}
    }
}

感谢lz 感谢thynson 感谢bccn````  好帖啊!

呵呵  其实我还是希望thynson能将改过的代码一下
我想看看正规的c++应该怎么写