EffectiveC++ Item11

这个item主要分析了防止对象自我赋值，利用copy-and-swap策略来解决。

写了小代码，其实在实际中大部分会简单写：

#include <iostream>
#include<string>
using namespace std;


class Widget
{
public:
Widget(int aData):m_Data(aData)
{
}
virtual void Swap(Widget &aRhs)
{
int lTemp = aRhs.m_Data;
aRhs.SetData(m_Data);
m_Data = lTemp;
}
Widget& operator=(const Widget &aRhs)
{
Widget lTemp(aRhs);
Swap(lTemp);
return *this;
}
int GetData() const
{
return m_Data;
}
void SetData(int aData)
{
m_Data = aData;
}
private:
int m_Data;
};
class Drived: public Widget
{
void Swap(Drived &aRhs)
{
Drived lTemp(aRhs);
aRhs = *this;
*this = lTemp;
}


private:
int m_DriveData;
};


int main()
{
Widget lTest1(10);
Widget lTest2(-10);
lTest2 = lTest1;
cout << lTest2.GetData() << endl;


}