//**********************
//**    ch15_1.cpp    **
//**********************

#include <iostream.h>
#include <string.h>

class Student{
public:
  Student(char* pName ="no name")
  {
    cout <<"create one student\n";
    strncpy(name, pName,40);
    name[39]='\0';
    noOfStudents++;            //靜態成員：每創建一個對象，學生人數增1
    cout <<noOfStudents <<endl;
  }
  ~Student()
  {
    cout <<"destruct one student\n";
    noOfStudents--;            //每析構一個對象，學生人數減1
    cout <<noOfStudents <<endl;
  }
  static int number()          //靜態成員函數
  {
    return noOfStudents;
  }
protected:
  static int noOfStudents;     //若寫成noOfStudents=0;則非法
  char name[40];
};
int Student::noOfStudents =0;  //靜態數據成員在類外分配空間和初始化

void fn()
{
  Student s1;
  Student s2;
  cout <<Student::number() <<endl;  //調用靜態成員函數用類名引導
}
void main()
{
  fn();
  cout <<Student::number() <<endl;  //調用靜態成員函數用類名引導
}