c++复习

include

using namespace std;
class ab
{
public:
!!!// ab(int m,int n):m(m),n(n){}
!!!// friend ab operator+(ab&p1,ab&p2);
void show();
private:
int m,n;
};
!!!//ab operator+(ab&p1,ab&p2)
{
return ab(p1.m+p2.m,p1.n+p2.n);
}
void ab::show()
{
cout<<"("<<m<<","<<n<<")"<<endl;
}
int main()
{
ab t(1,2);
ab t2(2,3);
ab t3=t+t2;
t3.show();
return 0;
}