析构函数显式调用

#include <iostream>
#include <string>
using namespace std;
class student
{
public:
	student()
	{
		cout << "constructing student." << endl;
		shours = 60;
		gpa = 6;
	}
	~student()
	{
		cout << "destructing student." << endl;
	}
private:
	int shours;
	int gpa;
};
class teacher
{
public:
	teacher()
	{
		cout << "constructing teacher ." << endl;
	}
	~teacher()
	{
		cout << "destructing teacher." << endl;
	}
};
void main()
{
	student stu1;
	teacher tea1;

	stu1.~student();
	tea1.~teacher();

	std::cout << sizeof(student) << endl;
	cout << "end in main" << endl;
}