为什么构造函数里的参数不能用字符串，要怎样用字符串做参数（“老师”那个参数）

//5.5
#include<iostream>
#include<string>
#include<string.h>
using namespace std;

class School
{
private:
string object;
string name;
int age;
int numeber;
int sex;
public:
School(string &object1,string &name1, int &age1, int &numeber1, char sex1)
{
if (sex1 == 'm')
sex = 0;
if (sex1 == 'f')
sex = 1;
age = age1;
numeber = numeber1;
name = name1;
object =object1;
}
int printf();
};
int School::printf()
{
cout << "身份：" << object << endl;
cout <<"姓名："<<name<<endl;
cout << "年龄: " << age<<endl;
if (sex == 0)
cout << "性别：男" << endl;
if (sex ==1)
cout<<"性别：女:"<<endl;
cout << "numeber:" << numeber << endl;
}

class Student :public School
{
private:
int ave_gar; //平均成绩
public:
Student(string &object1, string &name1, int &age1, int &numeber1, char sex1,int ave_gar1) :School
(object1, name1, age1, numeber1,sex1), ave_gar(ave_gar1)
{
cout << "平均成绩:" << ave_gar << endl;
}
};
class Teacher :public School
{
private:
string teacher; //教授的学科
public:
Teacher(string &object1, string &name1, int &age1, int &numeber1, char sex1, string &teacher1) :School
(object1,name1,age1,numeber1,sex1), teacher(teacher1)
{
cout << "教授的学科：" << teacher << endl;
}
};
class Staff :public School
{
private:
string work;
Staff(string &object1, string &name1, int &age1, int &numeber1, char sex1,string &work1):School
(object1, name1, age1,numeber1, sex1),work(work1)
{
cout << "工作类型：" << work<<endl;
}
};

int main()
{
Teacher a("教师","王一",32,2017320,'f',72);
a.printf();
Student b("学生","李二",15,2017203,'m',"语文");
b.printf();
Staff c("职工","赵三",28,2017256,'f',"清洁");
c.printf();
return 0;
}