用 c++设计人员类

#include<iostream>
using namespace std;
class CLIENT
{public:
CLIENT(char a){}
~CLIENT(){clientnum--;}
void shownum(){}
static void changeservername(){}
private:
char itsuser //客户机的使用者
static char servername;
static int clientnum;
};
//实现
char CLIENT::servername='windows xp';
int CLIENT::clientnum=0;
CLIENT::CLIENT(char a){itsuser=a;clientnum++;}
void CLIENT::shownum(){cout<<"客户数量:"<<clientnum<,endl;}
void CLIENT::changeservername(CLIENT c)
{   char a;
cout<<"请输入新的服务器名:"<<endl;
    cin>>a;
c.servername=a;
}
//测试
int main()
{CLIENT c;
c.servername;
 c.clientnum;
 c.shownum;