全局函数VS成员函数

#include <iostream>

using namespace std;

class  Test
{
public:
    Test(int a, int b)
    {
        this->a = a;
        this->b = b;
    }
    int getA()
    {
        return a;
    }
    int getB()
    {
        return b;
    }

    Test add(Test &t2)
    {
        this->a = this->a + t2.getA();
        this->b = this->b + t2.getB();
        //return *this;
    }
    void print()
    {
        cout << "a = " << a << "  b = " << b << endl;

    }
protected:
private:
    int a, b;
};

Test add(Test &t1, Test &t2)
{
    Test t3(t1.getA() + t2.getA(), t1.getB() + t2.getB());
    return t3;
}

int main()
{
    Test t1(1, 2);
    Test t2(2, 3);
    //Test t3 = add(t1, t2);
    t1.add(t2);
    t1.print();

    system("pause");
    return 0;
}

 成员函数隐藏了一个this指针,谁调用成员函数,this指针就指向谁,这个this指针就是指向调用成员函数的对象的首地址.

在成员函数里, *this 就是调用对象元素本身.一般用于return *this