在类模板中定义重载运算符模板函数，易错地方如下

例

错误（1）

#include <iostream>
using namespace std;
template <typename T>
class a
{
public:

a(T X,T Y)
{
x=X;
y=Y;
}
a operator ++();

void display()
{
cout<<"("<<x<<","<<y<<")"<<endl;
}
private:
T x,y;
};

template <typename T> a a<T>::operator++()
{
x++;
y++;
return *this;
}

int main()
{
a<int>point(534,54);
++point;
point.display();
return 0;
}

如上程序出现错误、~

正确：

（1）

#include <iostream>
using namespace std;
template <typename T>
class a
{
public:

a(T X,T Y)
{
x=X;
y=Y;
}
a operator ++()

{
x++;
y++;
return *this;
}

void display()
{
cout<<"("<<x<<","<<y<<")"<<endl;
}
private:
T x,y;
};

int main()
{
a<int>point(534,54);
++point;
point.display();
return 0;
}

正确

（2）

#include <iostream>
using namespace std;
template <typename T>
class a
{
public:
a(T X,T Y)
{
x=X;
y=Y;
}
a <T> operator ++();
void display();
T x,y;
};

template<typename T> a<T> a<T>::operator++()
{

x++;
y++;
return *this;

}

template<typename T> void a<T>::display()
{
cout<<"("<<x<<","<<y<<")"<<endl;
}
int main()
{
a<int>point(53,54);
++point;
point.display();
return 0;
}