问题__2018.06.17

代码：

#include <iostream>
using namespace std;
class a
{
public:
	a(int x):data(x) {}
private:
	int data;
	friend ostream& operator<<(ostream &out, const a &src);
};
ostream& operator<<(ostream &out,const a &src)
{
	out << src.data << endl;
	return out;
}
int main()
{
	a a(10);
	cout << a;
	int sex=100;
	cout << "sex=" << sex << endl;
	return 0;
}