#include <iostream.h>
#include <cstring>
class employee
{
public:
    employee(char *a,char*b,char*c,int d)
    {
        strcpy(ia,a);
        strcpy(ib,b);
        strcpy(ic,c);
        id=d;
    }
    display()
    {
        cout<<"姓名："<<ia<<endl;
        cout<<"地址："<<ib<<ic<<endl;
        cout<<"邮政编码"<<id;
    }
    ~employee();

protected:
    char ia[20];
    char ib[20];
    char ic[20];
    int id;
};
int main()
{
 employee a ("小红","长江中路2号","山东省青岛市",266520);
 a.display();
return 0;                                                                                                                                               
}

在编译的时候没有问题，但是在运行的时候却有两个问题，为error LNK2001: unresolved external symbol "public: __thiscall employee::~employee(void)" (??1employee@@QAE@XZ)
Debug/15.1.1.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

~employee();
即使不做什么也要加一对花括号，要不就干脆不定义析构函数也行。