求错误修正
#include <iostream>
using namespace std;

class date
{
public:
date() {}
void SetDay(int d){day=d;}
void SetMonth(int m){month = m;}
void SetYear(int y){year = y;}
void showdate();
private:
int year,month,day;
};

void date::showdate()
{
cout<<year<<"-"<<month<<"-"<<day<<endl;
}

class people
{
private:
char name[11];
char number[7];
char sex[3];
char id[16];
date d;
public:
people() {}
people(people &p);
~people() {}
void setname(char *);
void setnumber(char *);
void setsex(char *);
void setid(char *);
void setbirthday(date );
char *getname();
char *getnumber();
char *getsex();
char *getid();
void getbirthday();
void showpeople();
};

people::people(people &p):d(p.d)
{
strcpy(name,p.name);
strcpy(number,p.number);
strcpy(sex,p.sex);
strcpy(id,p.id);
}

void people::setname(char *newna)
{strcpy(name,newna);}
void people::setnumber(char *newno)
{strcpy(number,newno);}
void people::setsex(char *news)
{strcpy(sex,news);}
void people::setid(char *newid)
{strcpy(id,newid);}
void people::setbirthday (date d1)
{d=d1;}

char *people::getname (){return name;}
char *people::getnumber (){return number;}
char *people::getsex (){return sex;}
char *people::getid (){return id;}
void people::getbirthday (){d.showdate();}

class student : virtual public people
{
private:
char classno[7];
public:
student() {}
student(student &p);
~student() {}
void setclassno(char *);
void getclassno();
};

student::student(student &p)
{
strcpy(classno,p.classno);
}

void student::setclassno(char *newclassno)
{strcpy(classno,newclassno);}

char *student::getclassno (){return classno;}

class teacher : virtual public people
{
private:
char principalship[11];
char department[21];
public:
teacher() {}
~teacher() {}
void setprincipalship(char *);
void setdepartment(char *);
void getprincipalship();
void getdepartment();
};

void teacher::setprincipalship(char *newprincipalship)
{strcpy(principalship,newprincipalship);}
void teacher::setdepartment(char *newdepartment)
{strcpy(department,newdepartment);}

char *teacher::getprincipalship (){return principalship;}
char *teacher::getdepartment (){return department;}

class graduate : virtual public student
{
private:
char subject[21];
char teacheradviser[21];
public:
graduate(){}
~graduate(){}
void setsubject(char *);
void setteacheradviser(char *);
void getsubject();
void getteacheradviser();
};

void graduate::setsubject(char *newsubject)
{strcpy(subject,newsubject);}
void graduate::setteacheradviser(char *newta)
{strcpy(teacheradviser,newta);}

char *graduate::getsubject (){return subject;}
char *graduate::getteacheradviser (){return teacheradviser;}

class TA : public graduate,public teacher
{
public:
TA(){};
~TA(){};
};

#include "lab7_4.h"

void main()
{
char name[11];
char number[7];
char sex[3];
char id[16];
char classno[7];
char principalship[11];
char department[21];
char subject[21];
char teacheradviser[21];

TA a
cout<<"请输入人员编号：";
cin>>number;
a.setnumber(number);
cout<<"请输入人员姓名：";
cin>>name;
a.setname(name);
cout<<"请输入人员性别：";
cin>>sex;
a.setsex(sex);
cout<<"请输入人员id：";
cin>>id;
a.setid(id);
cout<<"请输入人员classno：";
cin>>classno;
a.setclassno(classno);
cout<<"请输入人员principalship：";
cin>>principalship;
a.setprincipalship(principalship);
cout<<"请输入人员department：";
cin>>department;
a.setdepartment(department);
cout<<"请输入人员subject：";
cin>>subject;
a.setsubject(subject);
cout<<"请输入人员teacheradviser：";
cin>>teacheradviser;
a.setteacheradviser(teacheradviser);

cout<<a.getname ()<<"\t"<<a.getnumber ()<<"\t"<<a.sex ()<<"\t"<<
a.getid ()<<"\t"<<a.getclassno ()<<"\t"<<a.getprincipalship ()<<"\t"<<
a.getdepartment ()<<"\t"<<a.getsubject ()<<"\t"<<a.teacheradviser ()<<"\t"<<
}

[解决办法]

C/C++ code

class date{public:    date() {}    void SetDay(int d){day=d;}    void SetMonth(int m){month = m;}    void SetYear(int y){year = y;}    void showdate();private:    int year,month,day;};void date::showdate(){    cout<<year<<"-"<<month<<"-"<<day<<endl;}class people{private:    char name[11];    char number[7];    char sex[3];    char id[16];    date d;public:    people() {}    people(people &p);    ~people() {}    void setname(char *);    void setnumber(char *);    void setsex(char *);    void setid(char *);    void setbirthday(date );    char *getname();    char *getnumber();    char *getsex();    char *getid();    void getbirthday();    void showpeople();};people::people(people &p):d(p.d){    strcpy(name,p.name);    strcpy(number,p.number);    strcpy(sex,p.sex);    strcpy(id,p.id);}void people::setname(char *newna){strcpy(name,newna);}void people::setnumber(char *newno){strcpy(number,newno);}void people::setsex(char *news){strcpy(sex,news);}void people::setid(char *newid){strcpy(id,newid);}void people::setbirthday (date d1){d=d1;}char *people::getname (){return name;}char *people::getnumber (){return number;}char *people::getsex (){return sex;}char *people::getid (){return id;}void people::getbirthday (){d.showdate();}class student : virtual public people{private:    char classno[7];public:    student() {}    student(student &p);    ~student() {}    void setclassno(char *);    char * getclassno();};student::student(student &p){    strcpy(classno,p.classno);}void student::setclassno(char *newclassno){strcpy(classno,newclassno);}char *student::getclassno (){return classno;}class teacher : virtual public people{private:    char principalship[11];    char department[21];public:    teacher() {}    ~teacher() {}    void setprincipalship(char *);    void setdepartment(char *);    char * getprincipalship();    char * getdepartment();};void teacher::setprincipalship(char *newprincipalship){strcpy(principalship,newprincipalship);}void teacher::setdepartment(char *newdepartment){strcpy(department,newdepartment);}char *teacher::getprincipalship(){return principalship;}char *teacher::getdepartment(){return department;}class graduate : virtual public student{private:    char subject[21];    char teacheradviser[21];public:    graduate(){}    ~graduate(){}    void setsubject(char *);    void setteacheradviser(char *);    char * getsubject();    char * getteacheradviser();};void graduate::setsubject(char *newsubject){strcpy(subject,newsubject);}void graduate::setteacheradviser(char *newta){strcpy(teacheradviser,newta);}char *graduate::getsubject (){return subject;}char *graduate::getteacheradviser (){return teacheradviser;}class TA : public graduate,public teacher{public:    TA(){};    ~TA(){};};//#include "lab7_4.h"void main(){    char name[11];    char number[7];    char sex[3];    char id[16];    char classno[7];    char principalship[11];    char department[21];    char subject[21];    char teacheradviser[21];    TA a;        cout<<"请输入人员编号：";    cin>>number;    a.setnumber(number);    cout<<"请输入人员姓名：";    cin>>name;    a.setname(name);    cout<<"请输入人员性别：";    cin>>sex;    a.setsex(sex);    cout<<"请输入人员id：";    cin>>id;    a.setid(id);    cout<<"请输入人员classno：";    cin>>classno;    a.setclassno(classno);    cout<<"请输入人员principalship：";    cin>>principalship;    a.setprincipalship(principalship);    cout<<"请输入人员department：";    cin>>department;    a.setdepartment(department);    cout<<"请输入人员subject：";    cin>>subject;    a.setsubject(subject);    cout<<"请输入人员teacheradviser：";    cin>>teacheradviser;    a.setteacheradviser(teacheradviser);    cout<<a.getname()<<"\t"<<a.getnumber()<<"\t"<<a.getsex()<<"\t"<<        a.getid ()<<"\t"<<a.getclassno()<<"\t"<<a.getprincipalship()<<"\t"<<        a.getdepartment()<<"\t"<<a.getsubject()<<"\t"<<a.getteacheradviser()<<"\t"<<endl;}