关于多重继承的一道程序

题目：定义Teacher类和Carde类，采用多重继承派生出Teacher_Carde类，要求在派生类的成员函数show中调用Teacher类中的display函数，输出信息，但是执行的时候display中的信息无法输出，求解答
#include <iostream>
#include <string>
using namespace std;
class Teacher                                 //Teacher类
{
public:
    void display();                          //输出函数
    Teacher(string n,int a,char s,string t);
protected:
    string name;                             //姓名   
    int age;                                 //年龄
    char sex;                                //性别   
    string title;                            //职称
};
void Teacher::display()
{
    cout<<"name:"<<endl;
    cout<<"age:"<<endl;
    cout<<"sex:"<<endl;
    cout<<"title:"<<endl;
}
Teacher::Teacher(string n,int a,char s,string t)
{
    name=n;
    age=a;
    sex=s;
    title=t;
}
class Cadre                                         //Cadre 类
{
public:
    Cadre(string n,int a,char s,string p);
protected:
    string name;
    int age;
    char sex;
    string post;
};
Cadre::Cadre(string n,int a,char s,string p)
{
    name=n;
    age=a;
    sex=s;
    post=p;
}
class Teacher_Cadre:public Teacher,public Cadre        //派生类
{
public:
    void show();
    Teacher_Cadre(string n,int a,char s,string t,string p,float w):Teacher(n,a,s,t),Cadre(n,a,s,p)
    {
        wages=w;  
    }
private:
    float wages;
};
void Teacher_Cadre::show()
{
    display();
    cout<<"post:"<<post1<<endl;
    cout<<"wage:"<<wages<<endl;
}
int main()
{   
    Teacher_Cadre t1("sun",20,'m',"teacher","jiaoshou",1234.5);
    t1.show();
    return 0;
}